CO2 injection rate for a 4' x 2' x 2' tank

[nivlekx]

Would like to know the recommended CO2 injection rate for a 4' x 2' x 2' tank. Plant load is quite heavy, fish load is rather high too, approx 20 tiger barbs, 1 aro and 1 pleco. pH is running high at the moment at 8. Going for 4 bps at the moment.

[bclee]

When you talk about CO2, always mention pH with KH. Only way to tell how much CO2 you have in your tank.

BC

[geoffrey]

What are you using to diffuse the CO2 into the water? Different method requires different BPS to achieve the desired level, which also mean that BPS is not a good indicator. Use the CO2/pH/KH relationship to determine whether you have enough.

[nivlekx]

Ok thanx. Will head to 328 to get a kH test kit later on. But my pH is quite high now at about 7.8.

[hoppinghippo]

there's no ONE exact bps per tank size, depends on delivery system, depends on rate of uptake by plants, depends on fish load producing co2, only way is to experiment yourself using ph-kh table, plus observing your plants.

[nivlekx]

I currently have a pH of 7.6 and a KH of 4, which corresponds to 3 ppm of CO2. Seems low. Gotta pump it up!!

[geoffrey]

Don't just pump up. Make sure the CO2 are diffusing effectively into the water otherwise most of it will end up in the air. Check you delivery system. We want to be environmentally friendly too by not letting out too much CO2.

[nivlekx]

Using a reactor, so dont think there will be any wastage. Unless I am ill-informed.

[tawauboy]

if you are using a reactor and getting only 3ppm,that could mean the test kits you are using are faulty, or the reactor is not doing it's job, or the 'so called' co2 that you are using is actually air.
in non-co2 injected aquariums, typical co2 levels are 1-3ppm.
do try to test your parameters again.

[David]

Which test kit did you buy anyway? Personally, I feel that KH test kit should be the liquid type and not the dip stick. Ensure that you count the number of droplets before it turns yellow.

As for PH, I rather go for the long term PH indicators rather than test kit...this would be monitor your CO2 injection better as it is always in your tank. However the only setback is that the liquid must be changed everytime you execute a water change.

If your tank is really at PH 7.6 and KH of 4, you are definately CO2 starved. KH 4 should be around PH 6.5...but before you start blasting your CO2, check the tubing that is not leaking, and that the flow-rate into the reactor is sufficient to do its job.

Do not lower you PH by more than 1 within 24 hours.

[nivlekx]

I think i found my problem. My tank is approximately 450 litres but my reactor's power head is only doing 500 L/H. Any implications?

[tawauboy]

are you using a power head to break up/dissolve co2?
don't think the capacity of the power head plays a big part. if you do not see big bubbles of co2 at the output of power head, it should be ok.

maybe you would like to elaborate more about your setup so that we can help you better.

[nivlekx]

My tank is a 4 x 2 x 2. Planted with aro. Currently using a Resun Canister filter, a reactor is attached to a powerhead supplying 500 L/H. Some how the CO2 dissolving rate is quite low. I still dont get why it is like that. When I pumped up the CO2, the pH dropped steadily from 7.9 to 7.5 but cant seem to go lower. And also, the needle valve always seems to supply less bubble count after some time. I always set it to approx 5 bps then next day i wake up its always less than 1 bps. Wierd.

[vinz]

Err... you need to fix the problem with the irregular injection rate first.

Btw, you don't have any kind of violent surface turbulanc or aeration, do you? No offence meant, but some arowana (or fish only) tank practices conflict with planted tank practices and the ill-informed hobbyist may not know it.

[vinz]

Forgot... the powerhead is good enough for the reactor.

[LLC]

And also, the needle valve always seems to supply less bubble count after some time. I always set it to approx 5 bps then next day i wake up its always less than 1 bps. Wierd.
--------------------------
I used to have this problem, it may be cause by the
needle valve. Problem stop after change it with a new
one brought from nature.[]

[nivlekx]

Vinz: No surface problems with my aro..

LLC: Think I will go get a new valve. Damn its going to cost me more "chick ching" again!!![]

[LLC]

Just to be sure, bring along your whole solenoid there
for Mr Chan to test. And to make sure the new valve fits.

[nivlekx]

After an afternoon nap, decided to go check on my tank and I made a startling new discovery. My KH just went up from 4-6, and pH remains stable at the 7.5-7.6 region. Somehow, the CO2 injection seems to be increasing the KH in my tank instead or dropping the pH. How should I go about addressing this problem? CO2 test kit? []

[PeterGwee]

Are you using coral chips? What kind of substrate are you using?