KH, PH and Co2

[chaq]

Hi, got some question after reading from dennerle's site that all 3 are related ... so what is the optimum condition for a fish tank?

Do i adjust the CO2 bubble rate or KH or PH?

If KH is what i need to adjust, how do i go about doing it?

If PH, add what?

Thanks

[bclee]

Usually, for planted tank you go for about 25 to 30 ppm.

Check the charts. If you have a target pH, just add sodium bicarbonate to increase the KH to that corresponding to the desired pH with CO2 of 25 to 30ppm. Maintain the bubbling so that the pH will drop to the desired level.

For example, if you need your water pH to be 6.5, raise the KH to about 3 or 4. (On the charts, you will find ph 6.5 and KH 3 will correspond to CO2 of 25 to 30ppm.) When you raise the KH, pH will rise. Then inject CO2, the pH will drop. Adjust the bubbling rate so that the pH will stabilise at 6.5.

If you are not particularing aiming for certain pH level, go for KH of about 3. Bubble CO2 until you reach the desire CO2 level.

Up KH: add sodium bicarbonate (baking soda) or KH up
down pH: add only CO2 (add any pH down products which are actually a weak acid, you will reduce KH too)

BC

[vinz]

Browse the Aquatic FAQ, info on raising KH using baking soda there. Chuck Gadd's website has info on the pH-KH-CO2 relationship, chart and some dosing info.

[chaq]

ok, thanks for the tip.

[Allen_1971]

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On 12/3/2002 3:10:36 PM

Usually, for planted tank you go for about 25 to 30 ppm.
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BClee,

Hey I think your levels are stated too high... optimum is usually from 10-20 or maybe 25.... 30 is a bit high already.

[bclee]

25-30ppm high?

I keep mine at 30-35ppm.[] IME, good for keeping algae away.

BC

[PeterGwee]

Bclee is a wild card...CO2 MANIAC!!!! [] I think beginners should aim for 10-20ppm for a start lah..much safer for your fish and shrimps...only after you have a good knowledge of how to set the CO2 should you attempt and I mean slowly..to increase to 30-35ppm if you are CO2 craze.

[Blades]

At what levels (PPM) would we expect to see bubbles emitting from the leaves of the plants?

[Allen_1971]

bubbling with your plants is not directly related to CO2... but rather photosynthesis... and also the saturation of the water with O2 (if you are thinking about seeing pearling). Also try and keep your CO2 to 20ppm. That should be more than sufficient for your plants while not risking your fish.

[Blades]

Currently , i have a 1 week old tank (125L) and parameters are as follows:

KH : 3 (Usually 3 for singapore Tap water rite)
PH : 6.9
that will give me a PPM of about 11

Question is , should i get the tank matured first before i increase my bps to drop my PH so i can get more PPM? rite now its about 1.5 bps.

Tank has denerlle substract with holland sand and also using FB7 and TR7. Tank is very quite planted and got a few starter fish in there too (2 x otos, a dozen or so shrimps (malayan&tiger) and aqbout 6 cardinal tetras)

[vinz]

KH: Sg tap water KH is ranges from 0 to 3 depending on location.

Someone correct me if I'm wrong, but your CO2 calculation may be inaccurate. TR7 is a peat extract and will lower your pH, affect your KH and thus affects your CO2 calculations.

If you're using CO2 injection, then only use CO2 and KH to control your pH.

You don't need to mature your tank to start increasing the bps.

[Blades]

Vinz , so how would you recommend me to increase my PPM for CO2? By increasing my BPS? but that would drop my PH too rite? to wat levels isit safe to drop the PH? i m trying to achieve around 20 PPM.

Thanks for any advice.

[PeterGwee]

Blades...since traces of peat is in your tank water already..I must say using the pH/KH relationship to judge CO2 level might not be that accurate anymore. But you can still try...Find your KH level and then look up the pH/KH chart to find the pH that will give you 20ppm. For example KH of 3..I will need a pH of 6.65 approximately to get 20ppm of CO2 (With injection of CO2 only! Not using peat to lower the pH!)

[Blades]

So wat you are saying is that if i attain PH of 6.7 thru the PH Pen test. This would give me a rough estimate of 20 PPM but the 20PPM might be actually 18-19 PPm due to the already present peat affecting the PH rite?

[PeterGwee]

Yup...but I must say the pH would not be stable at one pH value as long as CO2 injection is constant. So what you should do is to obtain the pH you desire at the end of the day before lights out.