hi all,

I've been injecting CO2 into my 4 ft tank using a pressurised CO2 and a Green reactor with 5 bio balls inside it..

After 2 weeks of injecting the CO2 this way ( the CO2 water level in the reactor remain constant all the time, bioball spinning round and round ) with 1 bps, my tank still show the following readings :

kH 3
pH 7.5 and translate to a very low CO2 ppm..

i've never been able to get the pH down to 7 or lower....


Any idea on how to increase the CO2 dissolve rate in the water ??

I usually put in 1 to 2 teaspoon of baking soda to increase the kH level after a 1/2 or 1/3 water change... is this what people usually do ??

Are there any other way to increase the kH level ??

Any advise/ideas to lower the pH by increasing the CO2 dissolve rate would be appreciated..


Thanks


Stanley

is there any bubbles coming out from the reactor? if yes, that's mean the co2 not really disolve in water. reduce the water flow rate if it is too strong.

try to increase from 1bps to 2-3bps n see. the ph will drop below 7 on next day.

errr...honestly, i nvr put this soda powder to increase PH. But sometime do use the KH up liquid to increase it.

There are tiny bubbles coming out of the reactor at the bottom... the rest of the CO2 gas is around 2 - 3 inch of CO2 spinning with the bioballs at the top.

hhmmm I find my flow rate okay... I actually wanted to put the CO2 reactor to the output of a power head instead of the canister filter outlet for a higher water flow rate.. the bioball spins super fast....

But if I increase the CO2 bps , the water level will drop to the point where the bioballs will not spin.... is this

I put in kH to increase the kH, but usually it will also increase the pH...

Without putting the baking soda, I find the kH at my place very low...


Stanley

1 bps is too little CO2 for a 4 foot tank, mine is running about 3-4 bps, what you're doing with the Kh powder is correct, as you're maintaining it to about 3dkH, pH will always go up when your KH increase, its normal, you inject CO2 to bring it down. But you really need to increase your CO2 injection until your pH drops to about 6.5, either get a better CO2 reactor or maybe, try it with your powerhead. What's your canister filter output anyway? I'm using an Eheim 2213 for my 4 feet, more than enough. Those green CO2 reactors with plastic balls are not very efficient. Stan, why not increase to 3 bps for a day or two and see how it goes?

Stand088,

why you need to increase the kh ? Try remove the baking soda. As I understand baking soda will increase PH.

As I know, if your change the KH and measure the PH, you won't get the actual CO2 contain.

I would recommand that you leaves the KH and PH as it is and increase your CO2. After a day or two, measure the KH nd PH to find out the CO2 contain.

Hope this helps solves your problem.

Actually I'm a little confused. Different people seem to have different opinions. Just how much KH is good KH? Some say 2, some say 4.

Refering to the CO2 chart...( KH and pH )

If your KH is 4, you need to bring down the pH to around 6.9 for optimum CO2 level.

If your KH is say 1, you need to bring down the pH to around 6.3 for the same CO2 level..

Of coz, when KH is increase using CaCO3 ( baking soda ), pH will raise too, so need to get the CO2 to be dissolve in the water to make the water more acidic ( lower pH )

Forgot about the detail chemical reaction...

Refer to the URL for the PH / KH / CO2 relation...
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm



Stanley

You're correct Stan, but from personal experience, if you have a kH of 4, bring the pH down to about 6.5 (about 30mg/l of CO2). I find this will stop and inhibit algae from growing, plants will bubble & grow very well too. Tangyp, there is no perfect Kh unless you're keeping really soft water plants like the Tonina species which really requires a kH of 1 or 2. But then your other plants won't grow that well. I recommend a Kh of at least 3 for sufficient buffer and not more than 8. Anything in btw is fine don't have to bother too much on this (In germany most people have a kh of 8 or more cuz they have hard water, but plants still grow well) kh and ph are just a balance of CO2 in the water, thats all. Gh should be more important cuz if this drops below 4 your plants might have problems growing and could be limited by the lack of Calcium & magnesium. a gH of around 6 would be good, not lower, higher is alright too.

for me...KH4-5 is the best. coz most of the plants need higher KH and of coz PH is 6.2-6.8.

Overdrive, remember you told me the tonina sp grow well under KH 0-1. But what i found from the magazine n forums said they do well in KH4-10. The old tank/setup is the best place for them to grow. as well as tonina fl.

The reason I ask is because my water KH is 0 and will need to add chemicals to top up the KH. The last time I used Sera's KH Plus. So don't want to overdo it. So I guess if I maintain KH to be about 4 - 5 should be alright lah. Thanks everyone!