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Co2 troubles

lidz87

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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
 

Tim Harrison

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

 

Zeus.

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5’x18”x2’ deep
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.
 

lidz87

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

ceg4048

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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,
 

sparkyweasel

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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.
 

lidz87

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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!
 

Easternlethal

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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

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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.

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.
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,
 

lidz87

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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.)
 

ceg4048

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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.
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.
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,
 

lidz87

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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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anewbie

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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.
 

lidz87

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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!
 

Easternlethal

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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

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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?
 

REDSTEVEO

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@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
20210503_105456.jpg
 

Andy Pierce

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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 ;)).
 

REDSTEVEO

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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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