# Co2 troubles



## lidz87 (30 Apr 2021)

Hi all

after some help and advice please. I have been toying with co2 again lately after 3-4 failed attempts in the past and failing again!

first of all about the tank
5’x18”x2’ deep
Fluval fx5 with 4.5” spray bar
Home made inline diffuser using water filter housing on Fluval outlet (have also tried inlet in the past) Iv also made different diffusers in the past of various sizes but this gives the best results. 
wave maker for extra circulation 
2x Fluval planted led 10 hour cycle with slow 2 hour ramp up and down. 

it seems nothing I do can turn the drop checker green. 
Iv turned up the bubbles per second so they are too fast to count (more than 6-8) 
I have turned them down to 3-4 and left it on for longer (5 hours before lights once)
Iv put it at 2bbs and left it on 24/7
Iv tried in tank diffusers x2 one at each end
Iv lost faith in the drop checker and bought others. 
Iv done ph and kh tests to check it manually (highest result 7.5ppm)
Even when the bubbles per second were over 8 I wasn’t getting fizzy water out of the spray bar so confident the co2 isn’t just blowing out of the spray bar or causing air locks and escaping all at once unnoticed
Done lots and lots of reading online and nobody seems to have this problem so thought I’d ask the experts for some pointers or things I haven’t thought of.
Thanks in advance
Martyn


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## Tim Harrison (30 Apr 2021)

Welcome to UKAPS. I'd seek the advice of @Zeus. 









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## Zeus. (30 Apr 2021)

lidz87 said:


> 5’x18”x2’ deep





lidz87 said:


> Iv turned up the bubbles per second so they are too fast to count (more than 6-8)
> I have turned them down to 3-4 and left it on for longer (5 hours before lights once)
> Iv put it at 2bbs and left it on 24/7


Big tank and not injecting enough CO2 IMO



CO2 used database for guidance on how long it lasts, doing a pH profile will also help and need to think CO2 is free as only then will you use it to its full potential IMO. The DC (if fitted correct) gives you a good indication of CO2 level and its to be trusted.


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## lidz87 (30 Apr 2021)

I did wonder if that was the reason but was worried about overdosing it. I will give it a try and report back.
Thanks!


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## ceg4048 (30 Apr 2021)

I agree with Zeus. There is no way to saturate a 5 foot tank with a measly 8 bps. At that size bps isn't meaningful. Increase the bubble rate until the DC turns green instead of setting an arbitrary rate and expecting the DC to cooperate.

Your target should be to drop the pH by about 1 unit within 1 to 2 hours. Forget about counting bubbles. That only works on small tanks.

Cheers,


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## sparkyweasel (30 Apr 2021)

lidz87 said:


> worried about overdosing it.


That is a valid concern if you have livestock in the tank. You need to make your adjustments when you are available to observe the inhabitants for any signs of distress.
If you haven't stocked the tank yet, you don't need to worry. Your plants won't come to any harm from overdoing the CO2.


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## lidz87 (30 Apr 2021)

Thanks all. Had it turned up for the last hour of the cycle and the dc started to change.
Yes the tank has fish. I lost a few on one of the previous times (few years back) when the dc was still blue. But I think that was a lack of surface movement as they were all ‘panting’ and at the top of the tank. a water change saved the rest and it scared me off for a while. 
also I have a 6.35kg cylinder so should last aprox a month according to the database thread linked. Thanks for that info!


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## Easternlethal (1 May 2021)

Well, you can see many posts in this forum where tanks appear to lack co2 despite having a yellow dc, and there is no plant in the world which needs a yellow dc to survive.

Also increasing flow sometimes just results in more co2 escaping. 

Another practical problem is flow severely limits the choice of critters and fish who like low flow, not to mention risking the comfort of livestock and ultimately requiring large pumps or many wavemakers and powerheads especially for a 5ft.

We should be really be encouraging people to properly understand the diffusion properties within their tank and how to combine the range of co2 injection methods available.


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## ceg4048 (1 May 2021)

Easternlethal said:


> We should be really be encouraging people to properly understand the diffusion properties within their tank and how to combine the range of co2 injection methods available.


Hi,
    Yes, agreed. That's why we encourage folks to study the sticky thread Water flow in the planted aquarium? as well as other threads regarding diffusion techniques.. Having said that, however, no understanding of diffusion properties will help unless the injection rate is appropriate. As mentioned in the other posts, an injection rate of 8 bps will not likely achieve the goals of the OP. Once the appropriate injection rate is achieved, then flow rate, distribution techniques an diffusion methods can be addressed to further optimize the tank.



lidz87 said:


> I lost a few on one of the previous times (few years back) when the dc was still blue. But I think that was a lack of surface movement as they were all ‘panting’ and at the top of the tank. a water change saved the rest and it scared me off for a while.


This has much less to do with surface movement than it does a failure of proper flow/distribution. The sticky thread I linked to discusses this issue.


lidz87 said:


> Fluval fx5 with 4.5” spray bar
> Home made inline diffuser using water filter housing on Fluval outlet (have also tried inlet in the past) Iv also made different diffusers in the past of various sizes but this gives the best results.
> wave maker for extra circulation


Again, unless we have a more detailed description or image of how the filter outlets or sprarybar and auxiliary pump outputs are arranged , as well  as what any mounting limitations are, then it is difficult to determine best placement. Many people gloss over these most pertinent details and simply state that such-and-such did not work, but images and sketches of the distribution method are crucial in understanding where the faults lay.

Cheers,


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## lidz87 (1 May 2021)

The spray bar is 4.5 feet long with a 5mm hole every inch. It is mounted just under the surface of the water along the back and sprays the water toward the front and angled down ever so slightly. 
the wave maker is halfway down the tank (deep) on the right side of the glass. Again angled slightly downward. I bought it as I was getting bba issues along with making the spray bar. Both were to rectify the flow issue. This has fixed the bba problem. 
With the current setup it takes 6-8 bubbles per second to drop to 6.9ph at 10dkh. Which meant I had to turn it down as that it 37ppm. It’s now closer to 6bps and will see how it results tomorrow (which is also water change day as I’m testing ei dosing currently.)


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## ceg4048 (1 May 2021)

lidz87 said:


> The spray bar is 4.5 feet long with a 5mm hole every inch. It is mounted just under the surface of the water along the back and sprays the water toward the front and angled down ever so slightly.


Thank you for the additional data. This is mistake #1. The holes in the spraybars should be angled _upwards _ever so slightly.


lidz87 said:


> the wave maker is halfway down the tank (deep) on the right side of the glass. Again angled slightly downward.


This is mistake #2. Any auxiliary pumps being used must supplement the output energy of spraybar by being place as closely as possible and directly below the spraybar at the midpoint of the spraybar length and should not be angled..  When the pump is place so far below the spraybar, it's effect is to actually cancel the energy of the spraybar flow by interfering with the flow coming down the front glass.


lidz87 said:


> 6.9ph at 10dkh. Which meant I had to turn it down as that it 37ppm.


This is impossible. It must be that you are reading the pH of the tank and then are using this reading in a pH/CO2 chart, which is the worst thing you can possibly do. The pH/KH/CO2 chart was never meant to take direct readings from a tank. The chart assumes that the only source of acid in the water is due to carbonic acid. Tank water has lots of other acids that disrupt the pH reading and almost always results in underestimating the CO2 content. Likewise, tank water should NOT be used in the DC. the pH/KH/CO2 chart will function perfectly only if the water inside the DC is distilled water adjusted to 4dKH, otherwise the reading is meaningless.

I now understand the nature of the difficulty. I suggest you make the adjustments to the flow/distribution via re-positioning and re-orientation of the pump/spraybar. It's still unclear how the diffusion is accomplished but one solution is to place the diffuser under the filter inlet in order to use the filter as the diffuser. You should also consider removing about 2/3rds of your filter media, assuming you have it filled, as most of the media is unnecessary and it penalizes flow throughput. This will make your FX5 much, much more efficient.

Cheers,


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## lidz87 (1 May 2021)

I will adjust everything tomorrow. Though I angle the spray bar down as too much surface movement causes too much evaporation and condenses on the lid of the tank. Which is wood (mdf coated in melamine I think) and I don’t want it to split etc. There is still a decent about of movement but the jets don’t ‘spray over’ the top of the water. It is set similarly to the half empty tank picture in the other thread you linked earlier. 
should I lower the spray bar so I can angle it up more?
Diffusion is done on the filter outlet with a filterless water filter housing and brass fittings. The water flows backwards through its normal use with a tube making the water come out at the bottom of it to adjust ate the co2 to help it diffuse.
I’ll also remove some of the media and spread it out within the trays more.
Thanks for your help


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## lidz87 (1 May 2021)




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## anewbie (1 May 2021)

I gave up on indicator and use a ph pen. I don't really care if the pen is accurate as much as the difference between before the co2 starts and stabilization after it has run a bit. Since i have fish tanks i tend to be conservative and aim for .7 drop. I test the ph near the injection point since i have some concern that the full tank is receiving an even dose. I have to warn you that those two sword plants are too close to each other and they will reach the top of the tank easily in a few months with co2. Also they will start sending out weekly runners which will add a bit to the annoyance. If you are going to inject co2 there are nicer swords - a couple that i like are prinz kleiner (reddish purple with good light and co2) and parvifolius tropica (about 2 inches high but nice leaves - make a nice carpet if you have 24 or so months). A smaller sword that has a nice leaf is Uruguayensis it will get 13-14 inches high with co2. Anyway there are hundreds of sword plants.


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## lidz87 (2 May 2021)

I have a ph pen which turned up today. It’s way better than the liquids you see in the picture. They show 0 change where the pen showed .8 drop.
The swords were put in a long time ago and may get changed in the future. 
there are two other tanks in my family so won’t be wasted. 
but they are a good test for now to see if the co2 is doing it’s job.
I’ll have a google of the plants you mentioned and choose from the pictures. Thanks!


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## Easternlethal (2 May 2021)

ceg4048 said:


> Hi,
> Yes, agreed. That's why we encourage folks to study the sticky thread Water flow in the planted aquarium? as well as other threads regarding diffusion techniques.. Having said that, however, no understanding of diffusion properties will help unless the injection rate is appropriate. As mentioned in the other posts, an injection rate of 8 bps will not likely achieve the goals of the OP. Once the appropriate injection rate is achieved, then flow rate, distribution techniques an diffusion methods can be addressed to further optimize the tank.
> 
> This has much less to do with surface movement than it does a failure of proper flow/distribution. The sticky thread I linked to discusses this issue.



These factors are all related and solved together - not linearly. So you wouldn't determine the injection rate first then fix flow/distribution because one determines the other. Surface movement, depth at which co2 is introduced, method etc. all affect the rate and will give a more precise result - so 8 is not enough but what is? 9? 15? 20? Should we always try to go for green in the dc? What about blue green? What if just blue? Surface movement effects may not factor in the solution, but is part of the problem and should be understood. Testing in order to determine the relationship in more depth before determining the solution is important - as some comments in the sticky have suggested. Not doing so is one of the reasons why there are still so many posts of people concerned about gassing their fish or not knowing the colour of dc to aim for, even as they try to address flow.

I am not saying your solution will not address OPs issue - just that evaluating the issue should be part of it and that can lead to other solutions.


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## lidz87 (2 May 2021)

ceg4048 said:


> Your target should be to drop the pH by about 1 unit within 1 to 2 hours. Forget about counting bubbles. That only works on small tanks.


I am achieving .9 ph drop in 2 hours. So pretty much there. 
Am I right in presuming that it should drop and stay there for the rest of the cycle? Or will it continue to drop after the 2 hour mark?


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## REDSTEVEO (3 May 2021)

@lidz87  I have been reading this with some interest. I've just rescaped my 400 litre Eheim Incpiria Aquarium and re-introduced injected CO2. 
Clive is right 99.9 % of the time based on my previous experience with planted tanks and as a member if UKAPS.

However....I am using a Dupla Drop Checker, no Spray Bar, and the only flow I have is from the outlet pipes of the two big Eheim Filters. The flow is aimed to the left and right side of the tank, and sort of circles round and meets in the middle at the front of the tank. 

I am using 2 x Colombo 3 in 1 CO2 Diffusers which are placed deep in the tank to the left and the right almost directly under the position of the outflow pipes. So it looks like the fine mist / bubbles that rise slowly towards the surface are being picked up by the outflow and swept around the tank in two different directions.

I have only one 6kg CO2 Bottle, with one regulator and one solenoid. But I have added a 2 way Splitter from CO2 Supermarket. At the moment I have only got 40 bubbles per minute going through each diffuser, which equates to 80 bubbles per minute. 

When I finished setting up the CO2 system and placed the Drop Checker in the tank the colour was very dark Blue. That was on Thursday last week. The CO2 is on a timer and comes on at 8am, stays on for 10 hours switching off at 6pm. 

I have a Fluval Aquasky and a Fluval Fresh Plant Pro 3.0 which come on for six hours only between 12pm and 6pm. The settings are very low at present (28%) capacity. All of the plants are established plants from another aquarium, with the exception of the Eleocharis Mini, which needs time to establish a decent root system.

If I believe what the in tank PH Probe is telling me, the PH is 7.5 at the time the CO2 comes on and within a few hours is reading around 6.8.

The Drop Checker is bright yellow, (see photograph)

The only issue I have at the moment is with the 2 way Splitter. As soon as I tweak on of them just the tiniest amount, the bubble rate goes uncontrollable and impossible to count. So I need to find out how to fine tune this.

Some of the best planted tanks I ever saw were in Germany, or at the Green Machine in Wrexham. Very low flow of water around the tank, drop checkers all light green and plants fizzing away like crazy. 

I suppose what I'm saying is it is horses for courses, and you try everything until you find what works for you. 

Good luck.

Steve


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## Andy Pierce (3 May 2021)

REDSTEVEO said:


> The only issue I have at the moment is with the 2 way Splitter. As soon as I tweak on of them just the tiniest amount, the bubble rate goes uncontrollable and impossible to count. So I need to find out how to fine tune this.


If your CO2 flow rate is really twitchy like this, I think you have two options:  1) reduce the CO2 pressure/flow upstream of the splitter with a flow restrictor and/or 2) upgrade the quality of your needle valves.  Your first and easiest step is to reduce the flow from the tank with the regulator, but in my experience this is of limited usefulness since regulators don't really fine-tune flow very well (at least not the one I have ).


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## REDSTEVEO (3 May 2021)

Andy Pierce said:


> If your CO2 flow rate is really twitchy like this, I think you have two options:  1) reduce the CO2 pressure/flow upstream of the splitter with a flow restrictor and/or 2) upgrade the quality of your needle valves.  Your first and easiest step is to reduce the flow from the tank with the regulator, but in my experience this is of limited usefulness since regulators don't really fine-tune flow very well (at least not the one I have ).


Doesn't the first stage needle valve act as a flow restrictor? I'm thinking if I turned that down, then the pressure to the splitter would be reduced allowing me to adjust those valves to increase the rate?


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## lidz87 (3 May 2021)

Have you tried balancing the splitter so it’s even and controlling the bpm on the regulator?


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## Zeus. (3 May 2021)

What @Hanuman was also talking about with me ( on one of our phone calls) is the cheapo needle value are not just hyper sensitive they are also unreliable, one day they give you one pH drop the next its another, this this my be related to small temp changes can have a dramatic effect on needle valves also, the cheap needle valves are better suited to high flow and are being used for low flow as they are cheap, Yes you can get lucky but the slightest movement of the needle valve and it does a different injection rate. The needle valves Hani has got (correct me if I am wrong m8) have to be turned say 90 degrees to increase from 6bps to 7 bps and not the slightest touch goes from 6BPS to 20BPS


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## Hanuman (3 May 2021)

Zeus. said:


> What @Hanuman was also talking about with me ( on one of our phone calls) is the cheapo needle value are not just hyper sensitive they are also unreliable, one day they give you one pH drop the next its another, this this my be related to small temp changes can have a dramatic effect on needle valves also, the cheap needle valves are better suited to high flow and are being used for low flow as they are cheap, Yes you can get lucky but the slightest movement of the needle valve and it does a different injection rate. The needle valves Hani has got (correct me if I am wrong m8) have to be turned say 90 degrees to increase from 6bps to 7 bps and not the slightest touch goes from 6BPS to 20BPS


Depends on the cv (coefficient of flow) of the needle valve. The lower the Cv the more turns you need to do to increase flow. The Swagelok M series has an 0.056mm orifice with a 0.03 Cv while the S series has a 0.032mm orifice with a 0.004 Cv.


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## Andy Pierce (3 May 2021)

Hanuman said:


> Depends on the cv (coefficient of flow) of the needle valve. The lower the Cv the more turns you need to do to increase flow. The Swagelok M series has an 0.056mm orifice with a 0.03 Cv while the S series has a 0.032mm orifice with a 0.004 Cv.


I think these Swagelok orifice sizes are actually inches, not mm ( www.swagelok.com/downloads/webcatalogs/en/MS-01-142.pdf ) so the S-series is 0.032" (0.81 mm) with a 0.004 Cv.  I picked up a second hand Hoke Micromite 1600 series (model 1656g4ya:  Item # 1656G4YA, Micromite 1600 Series On Hoke Inc. ) with a 0.031" (0.79 mm) orifice and a 0.0008 Cv which I thought would do the trick but was disappointed with it.  Maybe mine is defective but I get better performance at really low flow rates from this cheapo £22.50 model from Amazon ( www.amazon.co.uk/gp/product/B07TSHVX6B ).  I have them hooked up in series which did help.  For me anyway, adding a flow restrictor was the big difference maker where now I leave the Mircomite open (afraid to take it out of the inline setup in case things start leaking gas when I mess with it).  I confess to not having the physics expertise to understand how to use these parameters to calculate real-world flow rates so there was a certain amount of "try it and see" and to be fair, with a 45 L tank I do need really low CO2 injection flow rates.

Apols if bad form to link to another forum, but this is a pretty comprehensive list of options:  Metering(needle) valves for our DIY CO2 system


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## REDSTEVEO (3 May 2021)

Lights just going out now after being on for 6 hours and CO2 on for 10 hours.

Mosses and plants pearling, drop checker light green verging on yellow. Happy with progress so far.


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## REDSTEVEO (3 May 2021)

lidz87 said:


> Have you tried balancing the splitter so it’s even and controlling the bpm on the regulator?


No I haven't, at least not yet. I have managed to get both diffusers running at 60 BPM which is an increase of 20 BPM on each diffuser. So 120 BPM now. I am going to leave it alone now and reassess in a weeks time.


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## nigel bentley (3 May 2021)

ceg4048 said:


> Thank you for the additional data. This is mistake #1. The holes in the spraybars should be angled _upwards _ever so slightly.
> 
> This is mistake #2. Any auxiliary pumps being used must supplement the output energy of spraybar by being place as closely as possible and directly below the spraybar at the midpoint of the spraybar length and should not be angled..  When the pump is place so far below the spraybar, it's effect is to actually cancel the energy of the spraybar flow by interfering with the flow coming down the front glass.
> 
> ...


Hi Clive, 
Sorry to jump on someone's post, but I believe from your response, I'm doing 2 incorrect things. 
1) I use normal tap water in dc. Should I boil and let cool first?

2) Are show saying additional powerhead should be on back wall just under spray bars 
Not sure if I have missed the point 
Thanks Nigel


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## ceg4048 (3 May 2021)

nigel bentley said:


> Hi Clive,
> Sorry to jump on someone's post, but I believe from your response, I'm doing 2 incorrect things.
> 1) I use normal tap water in dc. Should I boil and let cool first?


Hi Nigel,
              The DC should be filled with distilled or RO water adjusted to 4dKH only. Tap water will have impurities that will currupt the readings. 4dKH water is sold by our sponsors as well as other on-line establishment. If you want to prepare it yourself you can just buy the distilled water and add carbonate salt measured out with an accurate scale, but it's so easy to find 4dKH water (or at least it should be). No substitute is acceptable.


nigel bentley said:


> 2) Are show saying additional powerhead should be on back wall just under spray bars
> Not sure if I have missed the point


Yes, the powerhead must supplement the energy of the spraybar. it's energy will pull the spraybars energy along to help get the water to the opposite glass, where it will be deflected downward. When water (or any fluid or object for that matter) has to change direction it loses energy. we are trying to send the water down the front glass where it has to change directions again by heading towards the back and then it must change directions again where we want it to climb up the rear wall. That's a LOT of energy loss, so the purpose of the pump is to act as a booster rocket, so it must send it's energy in exactly the same direction and must match, as closely as possible the energy vector of the spraybar.

Cheers,


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## ceg4048 (3 May 2021)

Easternlethal said:


> These factors are all related and solved together - not linearly. So you wouldn't determine the injection rate first then fix flow/distribution because one determines the other. Surface movement, depth at which co2 is introduced, method etc. all affect the rate and will give a more precise result - so 8 is not enough but what is? 9? 15? 20? Should we always try to go for green in the dc? What about blue green? What if just blue? Surface movement effects may not factor in the solution, but is part of the problem and should be understood. Testing in order to determine the relationship in more depth before determining the solution is important - as some comments in the sticky have suggested. Not doing so is one of the reasons why there are still so many posts of people concerned about gassing their fish or not knowing the colour of dc to aim for, even as they try to address flow.
> 
> I am not saying your solution will not address OPs issue - just that evaluating the issue should be part of it and that can lead to other solutions.


Hi,yes I fully agree with your point. I simply happen to know from experience, based on the size of the tank, that the 8 or 9 or 10 bps will never make the grade. We also happen to know anecdotally that blue DC is not good and that a bright lime green is the goal, especially in these days of overpowered lights. So the situation is not as vague as one might imagine. We have lots of other guides which provide the rules of thumb, yet, as you say, the finer points are not always understood. 
As the OP offered more information and as the situation was clarified we were able to provide the more holistic solution as you mentioned. Troubleshooting from afar is a two way street and the more information we receive the less guesswork and the less linearity is involved in the solution.

Cheers,


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## ceg4048 (4 May 2021)

lidz87 said:


> should I lower the spray bar so I can angle it up more?


Well, here's the thing: You really want to optimize your CO2/flow/distribution first and foremost. The penalty you may pay in the short term is to damage a few boards, but what you learn from implementing the procedures is worth more than a few boards. After you are able to optimize the behavior of the gas you can then make slight tweaks to determine how far you can stray from the "ideal" and still be within the correct regime. So yes, you can "get away" with lowering the  spraybar slightly, but if you lower it too far you will be forcing water to climb up the opposite pane as well as getting some of it to go down. The surface of the water acts as a kind of barrier forcing the water to mostly flow down. If there is too much splashing for your taste then instead of angling the holes up, just try to keep them at the horizontal (level).


lidz87 said:


> Diffusion is done on the filter outlet with a filterless water filter housing and brass fittings. The water flows backwards through its normal use with a tube making the water come out at the bottom of it to adjust ate the co2 to help it diffuse.
> I’ll also remove some of the media and spread it out within the trays more.


OK, cool. Thanks for the explanation. That diffuser seems OK and getting rid of some media will do wonders for your flow throughput and distribution.

Cheers,


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## Hanuman (4 May 2021)

Andy Pierce said:


> I think these Swagelok orifice sizes are actually inches, not mm


Correct. I'm metric biased. Hate inches. My brain unconsciously inverted the units.


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## nigel bentley (4 May 2021)

ceg4048 said:


> Hi Nigel,
> The DC should be filled with distilled or RO water adjusted to 4dKH only. Tap water will have impurities that will currupt the readings. 4dKH water is sold by our sponsors as well as other on-line establishment. If you want to prepare it yourself you can just buy the distilled water and add carbonate salt measured out with an accurate scale, but it's so easy to find 4dKH water (or at least it should be). No substitute is acceptable.
> 
> Yes, the powerhead must supplement the energy of the spraybar. it's energy will pull the spraybars energy along to help get the water to the opposite glass, where it will be deflected downward. When water (or any fluid or object for that matter) has to change direction it loses energy. we are trying to send the water down the front glass where it has to change directions again by heading towards the back and then it must change directions again where we want it to climb up the rear wall. That's a LOT of energy loss, so the purpose of the pump is to act as a booster rocket, so it must send it's energy in exactly the same direction and must match, as closely as possible the energy vector of the spraybar.
> ...


Thank you so much for your detailed response Clive. I've learnt two super things today and I can't wait to see the difference in moving the powerhead..Makes total sense, cheers mate


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## ForestDave (4 May 2021)

I’d look at trying smaller spraybar holes. I’m tinkering with mine at the moment I have a FX6 and a full width bar. If you have roughly 52 holes if they are spaced 1” apart. Then 3.5 mm diameter holes would add up to roughly the area of the 25mm pipe. This is sometimes mentioned as a good starting point.  I have 37 holes atm and have just tried 3.5mm which is a bit rough on the plants/critters but really pushes the flow down the front of the glass. I’m in the process of drilling them out to 4mm holes which should add up to around the correct area for the 25mm pipe. I reckon that should be about perfect for my tank but I’ll let you know how it goes.


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## ForestDave (4 May 2021)

I’ve just enlarged the holes to 4mm and the flow looks pretty good to me. Not that I know what the heck I’m doing! 😂 I had a pink flamingo crypt which was getting blasted before but now looks fine. This was my third set of tubes for the spraybar but I think I’m getting there now. I do like you also need a new needle valve as my CO2 Art one is rubbish and has the same issues as yours.


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## nigel bentley (4 May 2021)

ceg4048 said:


> Hi Nigel,
> The DC should be filled with distilled or RO water adjusted to 4dKH only. Tap water will have impurities that will currupt the readings. 4dKH water is sold by our sponsors as well as other on-line establishment. If you want to prepare it yourself you can just buy the distilled water and add carbonate salt measured out with an accurate scale, but it's so easy to find 4dKH water (or at least it should be). No substitute is acceptable.
> 
> Yes, the powerhead must supplement the energy of the spraybar. it's energy will pull the spraybars energy along to help get the water to the opposite glass, where it will be deflected downward. When water (or any fluid or object for that matter) has to change direction it loses energy. we are trying to send the water down the front glass where it has to change directions again by heading towards the back and then it must change directions again where we want it to climb up the rear wall. That's a LOT of energy loss, so the purpose of the pump is to act as a booster rocket, so it must send it's energy in exactly the same direction and must match, as closely as possible the energy vector of the spraybar.
> ...





ceg4048 said:


> Hi Nigel,
> The DC should be filled with distilled or RO water adjusted to 4dKH only. Tap water will have impurities that will currupt the readings. 4dKH water is sold by our sponsors as well as other on-line establishment. If you want to prepare it yourself you can just buy the distilled water and add carbonate salt measured out with an accurate scale, but it's so easy to find 4dKH water (or at least it should be). No substitute is acceptable.
> 
> Yes, the powerhead must supplement the energy of the spraybar. it's energy will pull the spraybars energy along to help get the water to the opposite glass, where it will be deflected downward. When water (or any fluid or object for that matter) has to change direction it loses energy. we are trying to send the water down the front glass where it has to change directions again by heading towards the back and then it must change directions again where we want it to climb up the rear wall. That's a LOT of energy loss, so the purpose of the pump is to act as a booster rocket, so it must send it's energy in exactly the same direction and must match, as closely as possible the energy vector of the spraybar.
> ...


Hi Clive, just repositioned powerhead and extended spraybar. Plenty of gaseous exchange once I replace co2 bottle. Does this look better do you think 
Thanks Nigel


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## nigel bentley (4 May 2021)

nigel bentley said:


> Hi Clive, just repositioned powerhead and extended spraybar. Plenty of gaseous exchange once I replace co2 bottle. Does this look better do you think
> Thanks Nigel


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## Easternlethal (5 May 2021)

just my personal preference but having such a big pump front and centre destroys the illusion of nature.. and looks like it has created a nice big hole in your substrate


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## Mooner (5 May 2021)

I would elect for two smaller pumps at 1/3 and 2/3 positions under the spray bar. Less intrusive than one large pump. Either way, the water has to be moved by some extra force.


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## ceg4048 (5 May 2021)

nigel bentley said:


> Hi Clive, just repositioned powerhead and extended spraybar. Plenty of gaseous exchange once I replace co2 bottle. Does this look better do you think


Hi Nigel,
           Yes that's the right idea but I agree with Easternlethal and Mooner that it's such an obnoxious looking pump. I assumed incorrectly that you had something more petite, like a Koralia or similar. Adding multiple and much smaller powerheads will satisfy flow requirements as well as the aesthetic appeal.

Cheers,


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## lidz87 (5 May 2021)

I too have made some adjustments to my spray bar and powerhead. Noticing less debris build up around the roots of the plants and actually prefer not looking at the powerhead. You can also see surface movement now also. 
Co2 is pretty much set just maybe some fine tuning. 
I’m noticing new growth on all of the plants daily which is very exciting.
 Thank you to everyone for your help! Such a great forum with many helpful people with sound advice


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## nigel bentley (6 May 2021)

ceg4048 said:


> Hi Nigel,
> Yes that's the right idea but I agree with Easternlethal and Mooner that it's such an obnoxious looking pump. I assumed incorrectly that you had something more petite, like a Koralia or similar. Adding multiple and much smaller powerheads will satisfy flow requirements as well as the aesthetic appeal.
> 
> Cheers,


Hi Clive, you are so right it's even created a hole in the substrate at the front.😂 Time to rethink, I will investigate into maybe 2 off the Koralia smaller pumps. 
Thanks again


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## nigel bentley (6 May 2021)

I was thinking of going for two Koralia Nano1600. With the two external Aqua one filters, this will give me a x11 turnover even allowing for filter media and pipes etc. I think disregard huge powerhead will have a three fold bonus
1) Better water distribution 
2) Less disruption for fish and plants 
3)Will look nicer 
Thanks for your help Clive


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## Easternlethal (7 May 2021)

Okay so this is thread is demonstrating what happens when we try to solve co2 distribution through flow without understanding diffusion.

Some people may know that takashi amano was fascinated by marine photography and consulted with oceanographers when refining co2 products for his ada brand. This is because oceanographers study fluid gas exchanges between the ocean and atmosphere. There is every good summary of the models studied here:








						Near Surface Turbulence and Gas Exchange Across the Air-Sea Interface
					

Open access peer-reviewed chapter




					www.intechopen.com
				




There are various factors that contribute to gas exchange across a water surface: a) the boundary between the water and air (thickness, depth, and viscosity)( b) effect of current in creating turbulence at this layer (called 'eddies') and (c) effect of deeper layers underneath.

The same applies inside a tank and can be illustrated by this diagram:






So applying all this theory to your single pump configuration, the strong flow will cause turbulence at the top layer and a strong current underneath which will probably resulting in more co2 escaping than being distributed.





This is why I'm not generally a fan of powerheads in distribution flow.


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## ceg4048 (7 May 2021)

Easternlethal said:


> So applying all this theory to your single pump configuration, the strong flow will cause turbulence at the top layer and a strong current underneath which will probably resulting in more co2 escaping than being distributed.
> 
> This is why I'm not generally a fan of powerheads in distribution flow.


Yes, I  also prefer to have a more muscular filter, but I think Nigel is getting the picture now. It takes a while to learn this stuff. Hobbyists are not experts in oceanography or in computational fluid dynamics, so even when we offer sound advice, it's from10,000 miles away, we don't always see the whole picture and information can easily be misinterpreted. This is simply the nature of learning.
As you mentioned there is an optimal range of flow rate across the leaf surface, below which the boundary layer thickness is too high and which attenuates gas transfer. Above which simply batters the leaf and reduces contact time between the gas and the leaf.
Laminar flow across the leaf reduces the boundary layer thickness and allows penetration of the gas to the leaf membrane. We get all that. ADA hideously overpriced gear does not necessarily perform any better than simple DIY. One just needs to understand the basics of flow/distribution in order to conjure up a viable scheme.
In many cases, however, we've seen where the filter flow to the spray bars is insufficient and must therefore be augmented with the powerheads. This is a lot less expensive than buying a new filter, so there is an economic imperative as well.

Cheers,


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## Easternlethal (7 May 2021)

Yes I know I'm belabouring things a bit and probably going over stuff that most people understand instinctively or have discussed already.

But I would like to do is propose a process that's just a bit more methodical as it can be helpful when our instincts don't produce the desired results. It's something I go through many times myself when fine tuning a tank, especially if I'm stuck with a certain aesthetic and don't have the flexibility to add more equipment or change flow direction. It can also help when extra fine tuning is needed later when plant mass changes.

So after thinking about how co2 interacts with the boundary layer in the tank, we can look at what kind of pump action we want. Do we want the pump to a) increase dwell time, b) deliver co2 somewhere specific or c) create turbulence? In this particular case we would want a) because the spraybar at the back is delivering even co2 across the width of the tank already along the surface to the front. Setting these objectives is really important because they can be different for each tank.

So the analysis would run something along the lines of: For a) we want something that can force fine bubbles deep below the tank and b) could be difficult because a pump itself is not providing any co2 because it is just moving water and we probably don't want c) it it drives out co2.

So for pumps we have to be much more sensitive to how it interacts with current from the spraybar and hard to get right even for experts, especially if it has limited flow power adjustments and narrow dispersion for the tank's configuration.

And the consideration of various solutions might involve: a) recognising that multiple smaller pumps might produce more evenly distributed power but the dispersion needs to be wide enough: b) considering whether wavemakers make things even more complicated and hard to control due to the eddies they create; c) evaluating whether the available pumps have sufficient control options d) looking at the type of nozzle - e.g should we use a normal nozzle, flat tip or wavemaker; e) exploring all available options - might a diffuser be better (especially if it's just one spot that Co2 is needed f) what about strengthening the filter pump or if not possible, g) supplementing it with additional atomisers, this quite common for weak filters?

Pump nozzle / output options




Non co2 injected pump configuration options:





These are just examples of things to consider before just reaching for the nearest available pump.

Then we might conclude that we want something with wide dispersion that matches or is just below the power at the spraybar better control or maybe we can add another line to the pump so that it can deliver co2 directly.

Getting into the minutiae of these tiny decisions are what makes the difference between a pro tank and an amateur tank.


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## ceg4048 (8 May 2021)

Hi,
    Yes this is reasonable. Sometimes economics plays a role as well which may hinder some options. In any case, I don't think life has to be so complicated all the time if we are able to stick to the fundamentals. As noted in our sticky, we suggest spraybars mounted close to the surface facing horizontal and enough muscle from the filter(s) to push the water down to the substrate level. The diffusion technique also has to be excellent. An inline device works best and it must produce very fine bubbles. If the bubbles are even slightly large their buoyancy allows them to escape to the surface against the downward push of the filter flow, so many of the bubbles will fail to reach the plant beds. This is just our basic blueprint which we can deviate from as the configuration of the tank varies. Wavemakers and other adjuncts become necessary when the fundamental  property of the filter do not meet the most important criterion - throughput.

Cheers,


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## Easternlethal (8 May 2021)

Its not really all that complicated and growing to love these details is part of the journey imo

Sent from my LM-V405 using Tapatalk


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