# My pH profile



## Sacha (6 Feb 2014)

I have just completed a pH profile for today. 






Time is along the x- axis, pH is along the y- axis. 

12:30 = Co2 ON

14:00 = Lights ON 

21:00 = Co2 OFF

22:30 = Lights OFF


KH is approximately 2.7

According to a few charts, I am achieving approximately 30 PPM Co2 concentration around 19:00. 

Does this profile look ok, and is there anything I can do to improve my Co2/ lights schedule? 

Is the Co2 coming on early enough? At lights on (14:00), pH was 6.7. This equates to a Co2 concentration of approximately 16-17 PPM. Is that acceptable, or should it ideally be higher?

I appreciate any input.


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## Puntius (7 Feb 2014)

Hi,

You should have a full unit drop by the time your lights come on, this is the most critical time to have the highest concentration of co2 in your tank when lights come one.

Another thing also to consider is the following, how many lights do you have on this tank if say you are using 4 x 54w t5 then let 2 x 54w go on at 14h00 and then the other 2 x 54w at 15h00

Reason for this is the plants needs to kind of warm up to starting working properly with the co2 to start using the food it makes.

The point I am trying to make is you need to try and have your co2 at 30ppm when the lights go on.

So your problem is probably that you dont have sufficient flow and distribution in your tank, this can cause the co2 not to distribute enough into your tank.

What method of co2 diffusion are you using this can also be one of your problems.

Please give us some more info regarding this.


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## parotet (7 Feb 2014)

Sacha, the deepest part of the valley in your graph should be at the time when lights are switched on... And I guess the pH drop could be improved as your KH is not really high. I recently did some pH readings to adjust the co2 flow in my tank with a kH that probably is around 10-12 and I finally managed to have a drop of 0,7-1... But this was done improving the flow (setting up a spraybar), reducing the amount of filtering media in the canister, increasing the bubble rate and changing to an atomizer system. Each change was a little improvement in my readings.
Another important thing to achieve is a stable pH once you have reached this deepest part on your graph, you want the high CO2 levels in your tank during the light hours and at least until some hours before lights are switched off.

I agree with Hannes that another way would be to switch on the lights little by little, so the CO2 demand is not so high at lights on and your plants will not suffer in case you do not achieve the optimum levels.

Not an expert, but I had to do most of this things in the last weeks


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## ceg4048 (7 Feb 2014)

Sacha said:


> Is the Co2 coming on early enough? At lights on (14:00), pH was 6.7. This equates to a Co2 concentration of approximately 16-17 PPM.


This doesn't equate to anything. As discussed previously, you cannot use the table to determine absolute values of CO2. You need to forget about calculating CO2 and instead concentrate on looking at how the pH changes.

You need an injection rate increase because with that KH the pH should really fall rapidly. If the fish are suffering when you increase the injection rate then this tells you that your flow and distribution are suspect.

Cheers,


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## Sacha (7 Feb 2014)

Thanks for all the replies. 

Clive, I am reluctant to increase my bubble rate, because the drop checker is nearly yellow by the evening. 

My flow and distribution are pretty good I think. I have a spray bar and an internal powerhead. The tank is 125 litres, and I have a 1000 lph internal, and a 1400 lph external. I recently switched from an in- line atomizer to an in- tank diffuser, because I don't like the micro bubbles that I get with the atomizer. So far I appear to be actually getting better distribution with the in- tank diffuser.


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## ceg4048 (7 Feb 2014)

OK, well what do the plants look like? What do the fish look like? Is the DC filled with 4dKH water? What was the pH profile with the atomizer in comparison?

There are a hundred possibilities. CO2 is an art form. It is not just a button press. You have to be home to monitor the tank during an injection rate increase. You may have more headroom than you think, or you may need to play with the distribution via placement of the pump outlets.

Cheers,


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## Sacha (7 Feb 2014)

The fish are fine.. 

The plants only start pearling in the evening, maybe 6-7 pm. 

Yes 4dKH in the drop checker. 

I never did a profile with the atomizer so I can't compare. 

Lighting is 2x 28w T5


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## Sacha (7 Feb 2014)

Hannes said:


> Hi,
> 
> You should have a full unit drop by the time your lights come on.




I keep seeing this advice on this forum. To me it seems very odd. 

A full unit drop in a tank of KH 2 equates to a minor increase in Co2. 

A full unit drop in a tank of KH 12 equates to a much larger increase in Co2. 

How can this advice possibly be correct, when every tank has a different buffering capacity? A "full unit drop" will equate to a different Co2 increase in every tank...


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## ceg4048 (7 Feb 2014)

The rest of the advice goes like this:
"If you have a low KH then you need a much larger drop by lights on"
"If yuo have very high KH then you may not need a 1 unit drop. A 0.5 unit (or so) drop may suffice"

Few people in UK have low KH, so generally a 1 unit drop is the target.

If your fish are fine then you can improve the injection rate, but be there to monitor.

Cheers,



Sacha said:


> The plants only start pearling in the evening, maybe 6-7 pm.


Ideally, plants should be pearling by about 1 hour after lights on.
HOWEVER......if you are not having any CO2 related algae then the advice is to leave things be.

This MAY become a problem as the plant mass increases, but right now, if the plants are fine and if the fish is fine then ignore all the advice. If you have a problem then pay attention to the advice.

Cheers,


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## Sacha (7 Feb 2014)

Thanks for all the advice. 

I think today I will set the co2 to come on/ go off 2 hours before the lights as opposed to 90 minutes. I will also slightly increase the bubble rate. 

If the drop checker goes yellow, I'll turn it back down?


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## Sacha (7 Feb 2014)

Clive, I don't have a *problem*. I just want to completely optimize the Co2 injection


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## Puntius (7 Feb 2014)

I have learned from our expert Clive that a Drop checker is only a rough guide, and that your fish will tell you at the end of the day if your co2 is to high then just turn it down a bit until they are fine.


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## Sacha (7 Feb 2014)

By the time the fish tell you, they are already suffering. Ideally I  Don't want to get to that point


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## Puntius (7 Feb 2014)

Yeah that is true so rather leave things like it is currently or make your few adjustments.


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## Rob P (7 Feb 2014)

It looks as if your PH max to min drop happens over 5 or 6 hours? That's a problem i'd say?

My gas comes on at 1.15pm ph7.4 and by 3pm (lights start ramp up) it's ph6.3. There it stays until well into light ramp down at 9.30pm (gas off 8.20pm).


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## Sacha (7 Feb 2014)

Well today I have set the Co2 to come on/ go off 30 minutes earlier, and I have slightly increased the bubble rate. I have started a pH profile but I was only able to take the first reading at 12.15 (Co2 comes on at 12), so I don't know what the pH was at 11 am.


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## Rob P (7 Feb 2014)

But it looks to be more an issue of how long your PH drops over as opposed to on/off timings. So if it comes on 30 minutes earlier but if it still takes 5 or 6 hours to drop this isn't much good.

A lengthy drop suggests to me (IME) poor dissolution method coupled with poor flow/distribution. For me putting a long spray bar on the rear and inline atty made all the difference...


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## Sacha (7 Feb 2014)

I will switch back to my atomizer then. Although I really don't like the micro bubbles that it chucks out. I don't think my flow can possibly be poor. I have (rated) 2400 lph on a 125 litre tank.


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## Rob P (7 Feb 2014)

It's hard work isn't it?! lol


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## Sacha (7 Feb 2014)

Yeah it really is. 

Just out of interest, what angle is your spray bar pointed at?


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## Rob P (7 Feb 2014)

Mine angles up slightly (not enough to shoot it out of the tank should I spring a leak!) so I get a decent surface agitation without breaking the surface. After weeks of messing around I found this the best balance at the expense of having to raise bubble rate a smidge. A few extra pennies in gas here and there for the wellbeing of the fish is not a problematic compromise for me.

But I accept it is all hard work. I once did my water change and filled like an extra 5mm which reduced surface movement significantly and the difference to fauna was quite notable. So i've found even taking off spray bars to clean, or doing water changes etc I'm always paying critcal attention to return things to how they are when it all 'works' lol


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## Sacha (7 Feb 2014)

If it angles up, then doesn't the Co2 through the spray bar just go straight to the surface and gas out of the water...


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## Rob P (7 Feb 2014)

No, there's a clear supply of co2 getting blasted down the front pane. It's a tetratec 1200 with about 50% media removed in 125l tank providing the cojones lol


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## ceg4048 (7 Feb 2014)

Sacha said:


> By the time the fish tell you, they are already suffering. Ideally I Don't want to get to that point


This is not true at all. If you are monitoring the tank, as suggested, and if you see the fish in distress, all you have to do is to perform a massive water change. The fish will begin to recover immediately.




Sacha said:


> Just out of interest, what angle is your spray bar pointed at?


Spraybars should be pointed horizontally.




Sacha said:


> I will switch back to my atomizer then. Although I really don't like the micro bubbles that it chucks out. I don't think my flow can possibly be poor. I have (rated) 2400 lph on a 125 litre tank.


You don't have to use the atomizer. You can simply port the gas into the filter suction tube and let the filter be your atomizer.

Cheers,


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## Sacha (7 Feb 2014)

Here is a pH profile for today:







12:00 = Co2 ON

14:00 = Lights ON

20:30 = Co2 OFF

22:30 = Lights OFF


I increased the bubble rate and had the Co2 come on a bit earlier.

At around 19:00, I got the sense the fish were a bit uncomfortable. So I reduced the bubble rate.

The drop checker is also yellow, if that means anything. 

Does this look any better?

I know that those pH/ KH charts can't be trusted. However, according to those charts, my Co2 is way above lethal levels. 

Will be switching back to the in- line atomizer over the weekend probably, and will do another profile next week.


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## Ian Holdich (8 Feb 2014)

All this messing with c02 WILL result in bba...just be very careful messing with it, as Clive states, if it ain't broke don't fix it. 

I'm going to let you into a little secret now. I have never used a drop checker as I couldn't read them very well, as I do have a little colour blindness. I monitored everything very closely at the start. Six years later and I've never lost a fish to c02 related problems. I also just set my bubble rate to 1-2 bps and just leave it. Ime plants like a consistent amount of c02, any change will result in c02 related algae.


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## Sacha (8 Feb 2014)

Thank you Ian. 

What prompted me to make this change was the fact that I see a lot more pearling in other tanks than in mine. Also I know I should be seeing a larger drop in pH than I am seeing. Will switch back to the inline atomizer, do a pH profile then, and post it on this thread.


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## NatureBoy (8 Feb 2014)

This is the best thread I've read on ph profiles: Tom Barr and others put forward some nice profiles and how to achieve them. The emphasis is on establishing a nice equilibrium ph profile / dissolved CO2 conc throughout the light period: CO2/pH level in planted tank | Page 2 | UK Aquatic Plant Society

I learnt a lot from this and by following the links / suggestions.


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## Sacha (8 Feb 2014)

OK so this is what I have learned so far:

My pH profile is too "pointed". I want a more flat, constant pH profile.

Ideally I want the pH to reach its lowest point around lights on, and stay there until a couple of hours before lights off, when it should start to rise again.

The easiest way to achieve this is to increase the bubble rate, while creating some surface agitation? 

Is that really the only way to achieve the "flat" profile I want- I have to gas out some of the Co2?


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## NatureBoy (8 Feb 2014)

...yep, by matching gas in and gas off you reach a constant level. Higher rate + surface agitation is one way, particularly if you want to drive the gas off at night.

What I do though is low surface agitation / much lower rate (start a couple of hours before lights on) with no gassing off at night. Before injection in the morning this means there is still some CO2 kicking around and means I don't have to inject as much CO2. There is no distress to the fauna 24/7. I inject inline which gives me good dissolution and distribution around the tank.

First try higher rate with higher surface agitation as this gives you more margin for error whilst you are finding the balance points (airstones don't cut it, you need a powerhead to break the surface and get good gas interchange), and plot a PH profile, hopefully you'll see for yourself how it plateaus at a given rate. 

If you want pearling make sure the plants have all the nutrients they need. Phosphates would be my tip to try adding a bit more of, but don't skimp on any of course!

cheers


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## pepedopolous (13 Feb 2014)

Hey guys,

This thread (and those linked) have been so helpful. Thanks!
My current profile (125 litre aquarium, UP inline atomiser, ~3 bubbles per second): -





I think in my case, surface scum was interfering with the gas exchange (even though I had a Koralia blasting the surface). I've replaced the Koralia with an Eheim Skim 350 and now there is a ~1 pH unit drop before lights on which then levels out and doesn't distress the fish.

P


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## NatureBoy (13 Feb 2014)

That looks about perfect well done!

Another thing to note is that any change in pH caused by plant uptake of CO2 seems to be minimal to non existent compared to the gas in / off equilibrium...ie it still plateaus no matter what the level of photosynthesis...


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## pepedopolous (13 Feb 2014)

Thanks 


NatureBoy said:


> Another thing to note is that any change in pH caused by plant uptake of CO2 seems to be minimal to non existent compared to the gas in / off equilibrium...ie it still plateaus no matter what the level of photosynthesis...


 
I wonder how much CO2 the plants produce by respiration? Even with all the surface agitation, it seems to take ages for the pH to rise.


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## NatureBoy (13 Feb 2014)

hmm looks like an exponential fall in pH and then a natural logarithmic climb in pH...where's the geek symbol?


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## plantbrain (14 Feb 2014)

When I had canisters on my tanks I measured about 20 ppm of CO2, when I switched over to wet.drys, I had 3 ppm of CO2 at the night time.
Scum on the surface, quite a few things can mess with it.

What you want is an ideal mesa like concentration:


Your CO2 is more like this: but not as high to reach the lethal thresh hold. Basically you likely only have 15 ppm or thereabouts.





You can make the mesa shape and get the CO2 up faster with better mixing, more flow etc, and with a higher CO2 bubble rate etc.
 BUT...........you do not want to hit the lethal thresh hold. So go slow and consider several ways to add CO2 up to a point, then it's "wasted". This will give you a nice mesa shape without any controllers(which is yet another method to do it).

A single action purge tube inside a reactor will do this quiet easily, basically the reactor will dissolve 100% of the CO2 up to a pre set level inside the reactor. Gas builds up later in the day cycle and this can purged, or wasted as a mist.
Typically the last 1/2 or less of the lighting CO2 cycle.

the height inside the CO2 reactor can be adjusted to suit also. Some chose 1/2 way down, some chose 3/4th etc.

Works just like a regular reactor unit till the level reaches the rigid air tubing you add and this has an airline that loops back to the main filter pump etc and sucks the gas in and spits it out into the tank.


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## Sacha (17 Feb 2014)

Here is a pH profile I made today:






12:00- Co2 ON 
14:00- Lights ON
20:30- Co2 OFF
22:30- Lights OFF

This is with quite a lot of surface agitation now (made by internal filter's pump), and the in- line atomizer.

How can I flatten this out more?


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## LondonDragon (17 Feb 2014)

Sacha said:


> How can I flatten this out more?


Why would you need too?


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## Sacha (17 Feb 2014)

Read the post previous to mine


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## LondonDragon (17 Feb 2014)

Sacha said:


> Read the post previous to mine


 
Just measure it using a drop checker and forget about PH!


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## pepedopolous (17 Feb 2014)

Sacha said:


> How can I flatten this out more?


 
If you have the time to observe the aquarium all day and keep an eye on the fish, increase the bubble count.

Hopefully the pH will drop faster and then flatten out due to degassing. 

Cheers,
P


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## LondonDragon (17 Feb 2014)

pepedopolous said:


> Hopefully the pH will drop faster and then flatten out due to degassing.


Won't you need to measure the KH also accurately before you can determine CO2 amounts in the tank? by just measuring PH is not enough on its own! Correct me if I am wrong!


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## Sacha (18 Feb 2014)

KH is 2.8. 

I'm not trying to measure an exact level of Co2 in PPM. I am trying to work out the Trend, so I can make it more constant throughout the day.


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## pepedopolous (18 Feb 2014)

Paulo,

You measure the change in pH during the time CO2 is on. Any other factors are unlikely to cause a significant change in pH during this time.

You aim for a ~ 1 unit drop in pH before lights on. From this point onwards de-gassing means the pH doesn't drop much further and you can have the CO2 on for as long as you need it. Livestock is unharmed and pearling happens very rapidly.

Of course all this absolutely depends on good surface agitation. 

P


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## Sacha (25 Feb 2014)

This is my pH profile, after creating surface agitation, and increasing the bubble rate: 




 

Co2 ON: 1200 
Lights ON: 1400

Co2 OFF: 2030
Lights OFF: 2230


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## Sacha (25 Feb 2014)

Does this look better?


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## pepedopolous (25 Feb 2014)

Yes! Is there much pearling? If so when does it start?


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## Sacha (25 Feb 2014)

There is a decent amount of pearling. I guess it starts around 4 pm (?) So around 2 hours after lights on.

Should I have the Co2 come on an hour earlier, so it reaches its peak (6.4) by the time the lights come on?


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## pepedopolous (25 Feb 2014)

Sacha said:


> There is a decent amount of pearling. I guess it starts around 4 pm (?) So around 2 hours after lights on.
> Should I have the Co2 come on an hour earlier, so it reaches its peak (6.4) by the time the lights come on?



I have the CO2 turn on three hours before lights on (and they take an hour to ramp up...). I think the pearling is a good sign. What about the plant growth?

P


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## Sacha (25 Feb 2014)

I'm getting good growth, but not as fast since I've decreased the photoperiod from 10 hours to 8.5.


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## ceg4048 (25 Feb 2014)

Sacha,
             That looks terrible. It takes 5 hours to drop the pH by 0.8 units? Not good, generally....

Cheers,


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## Sacha (25 Feb 2014)

What do you suggest I do? 

Using an inline atomizer with great circulation. Shall I increase the bubble rate even more?


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## ceg4048 (25 Feb 2014)

Yes, but don't vaporize your fish in the process. If the levels rise too much then just turn the gas off a few hours earlier.

Cheers,


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## Sacha (25 Feb 2014)

It seems counter- productive for me to create so much surface agitation, because it is meaning I am having to increase my bubble rate nearly 3x. Seems a waste of gas?


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## ceg4048 (25 Feb 2014)

Reduce the level of agitation. You ahve to play with all of these factors to flatten out the curve so that it approximates what you see in plantbrains post.

Cheers,


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## Sacha (1 Mar 2014)

So, I'm still trying to get the optimum pH profile....

Tell me what you think. 



 

pH drops from 7 to 6.5 in the first two hours of the Co2 being on. Isn't that a lot better?


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## ceg4048 (3 Mar 2014)

No. Still terrible.

Cheers,


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## Sacha (3 Mar 2014)

Great, thanks for the encouragement


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## ceg4048 (3 Mar 2014)

You specifically asked:


Sacha said:


> Tell me what you think.




So do you want truth, or is feeling good a better path to success?

Cheers,


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## Sacha (3 Mar 2014)

I appreciate all your patience and input on this thread. So we have established my profile is still terrible. The question is what do I do next? I'm not sure what more I can do without gassing my fish. I have no idea how one achieves such a steep slope as in Plantbrain's post.


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## ceg4048 (3 Mar 2014)

Are you using too much aeration?
Are you seeing distress in the fish when you increase the injection rate?
Are you sure that your KH is only around 3?
What is your distribution scheme and exactly haw is the gas being dissolved?

You have to get to the nitty-gritty. Each detail has an impact and must be investigated further.
If I were standing next to the tank it would be easier, but I'm forced to use only my imagination from hundreds of kilometers away. Got any images?

Cheers,


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## Sacha (3 Mar 2014)

This was the tank about 2 weeks ago:






Co2 is diffused via an inline UP atomizer. The spray bar is pointed very slightly down towards the front glass, at an angle of maybe 20 degrees. The external filter is rated for 1400 lph and the tank is 125 litres. There is also an internal 1000 lph Juwel Bioflow filter which is responsible for the surface agitation. A rated flow of 2400 LPH is more than enough in a 125L tank, is it not?

The KH is between 2.3 and 2.7. This is according to a (very reliable) Salifert titration method test kit. I trust it.

The internal filter is on the far right of the picture- not sure you can make it out. The water is pumped from the outlet horizontally along the back of the tank. The outlet is making a slight surface ripple. The last pH profile I posted here was after reducing the surface agitation quite significantly.

Please ask any more questions that might help you understand my tank better. I really do appreciate the time you are giving this thread. It may seem like I am being obsessive, but I want to get the balance in this tank just right, so once I have achieved that balance, I can hopefully stop worrying about the Co2 levels once and for all.

I can take more pics of specific areas of the tank if that would help.


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## Jafooli (3 Mar 2014)

Wow that tank looks amazing, I would not be worrying about my ph profile if it were mine. I would be to busy showing it off. But then again im an amateur plant grower and can fully understand you want the best for your plants from the start of the photoperiod to the end. But I for now can only wish to achieve a tank like that. The closest I ever get to pearling is the tiny bubbles after my water change lol. Good luck with your ph profile. Your obviously doing something right either way as your plants look real happy!


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## Sacha (3 Mar 2014)

Aww thanks a lot mate, much appreciated. Comments like that make it all worthwhile.


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## parotet (3 Mar 2014)

Hi, reading your thread I would suggest 4 things:

- switching on the CO2 2 hours before light on is not that much... I have a very high KH, don't know exactly how much but higher than yours, and I have to switch on my co2 3,5 hours before lights on to have a nice pH drop. You should reach a faster drop with your kH but try to switch on 3 hours before, for example, and measure if it works.

- as far as I have understood your spraybar jets are pointed towards the front glass, but the internal filter outflow is pointing along the back glass... This is not good as far as I know. The flow of one filter is decreasing the effectiveness of the other one. All the outflow jets have to work together.

- why do not increase the bps? In my tank I try to save that bullet for the end (I preferred to improve other issues that increase co2 effectiveness rather than injecting more and more), but if your fish are ok, increase the bubble rate. Every time I visit planted tank galleries I am amazed with the bubble rate folks use... Man, I cannot even count the bubbles! I know that bps is not a reliable indicator, but if you just want to have, as I do, 1 or max 2 bps, everything might be fine tuned.

-...and the very best one: reduce the light, take it easy, forget your algae problems and enjoy! I have some old plants leaves with some thread algae now but I can live with them... You know, life became much easier just raising 20 cm my light fixture. 

Hope it helps...  

Jordi


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## pepedopolous (3 Mar 2014)

That's one gorgeous looking aquarium!

I think Tom Barr is able to achieve such fast drops in pH because he uses a 'wet-dry filter'. This is basically a sump where the water leaving the aquarium is literally sprinkled down through some filter media. This allows for massive oxygenation and also degassing of injected CO2 which simply cannot be matched by the external filters or any other kind of filter more typically used.

For us mere mortals (using an internal or external canister filter), degassing of CO2 is a much slower process so we cannot inject at such high BPS without risking our livestock as the CO2 causes pH to drop too far. Likewise, it takes all night for the pH to rise once the CO2 is turned off.

We can't hope to achieve the same results as a 'wet-dry filter'.


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## Sacha (3 Mar 2014)

Thank you everyone for all the kind words and advice. It really is great to have feedback like that! 

Having read all these comments, I think what I am going to do now is just leave things be. The fish are happy and the plants are growing really well and I have no issues with algae etc. If I fiddle too much I might upset the balance. It has taken me a long time to get my tank to the stage it is at now, and I am very happy with it atm. So I don't want to risk losing that. 

Thank you everyone for all your help and advice. I am very grateful.


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## Samjpikey (4 Mar 2014)

Your tank looks really nice , you should be pleased with that  
What lighting do you have over it ?? 

I too have a 125 liter tank with a 1400lph external filter (aquamanta efx 400) , co2 diffused via inline  .
My kh is 4 and I am able to get a full drop in ph about an hour after co2 on. 

I haven't got a drop checker so can't compare that . 
I did have an 800lph powerhead diffused via a spray bar the full length of the tank but I removed it and now I seem to get a more of a drop in ph . 

Maybe turn the extra flow off for a day and see what drop you get ? 




Sent from my mobile telecommunications device


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## Samjpikey (4 Mar 2014)

Bps is around 2.5 jbl counter 


Sent from my mobile telecommunications device


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