CO2 / pH / kH Relationship

[George Farmer]

I'm thinking of using CO2 for my planted setup. I've pH 7.0 kH 3.5 gH 8 at the moment (I'm experimenting with small fluctuations using 100% RO and various supplements).

I'm aware CO2 lowers pH but does this by default lower kH? My plants seem to like the kH around 3 so would CO2 hinder this? Also what effect will the lower pH have? I suppose what I'm asking is, does the benefits of CO2 outweigh the possible negatives?

I'm thinking of buying one of those Nutrafin Reactor kits (yeast and sugar I think). They're cheap! Does anyone recommend them?

 

[George Farmer]

I've just read the CO2 link. All is clear now!!!

 

[mrV]

All is clear now!!!

Great, would you like to tell me too, because it's not so clear to me?

If some has tank with parameters:

pH 7
KH 10
tables show that there should be 32 mg/l CO2

So, Im really interested in what CO2 test shows. Because I don't believe those tables B) => Water of aqurium has different kind of compound, not only CO2 and karbonates. E.g. tannic acid, ammonium/ammonia...

 

[George Farmer]

That KH seems very high in relation to the pH. Are you using CO2?

The other 'compounds' as you say i.e. tannic acid, ammonia etc should be in realtively tiny proportions and shouldn't affect test results.

As the link says, the tables are only accurate if your buffering is purely provided by carbonates. Have you tested for phosphates? My tap water is about 7 ppm which is very high (one reason I use 100% RO).

I don't know if this has cleared anything up for you. There's plenty of other info on the net. Good luck.

 

[revengeishere]

Why does my tank, which is gh 20, kh of 6 and a ph of 7.8 dont change when I add co2? I know the plants are recieving them due to pearlings, but my ph level doenst change at all...hmmm.

 

[Great Lakes]

The harder your water, with a higher ph, the less fluctuation you will notice.

Hmmm...that sounded like something Yoda would say..lol

 

[mrV]

The other 'compounds' as you say i.e. tannic acid, ammonia etc should be in realtively tiny proportions and shouldn't affect test results.

But If I use peat-filtration? Or have lots of wood in tank? I think, I need to do those tests sometime when I have time to do it. I just don't believe those tables, because there is much more than carbonates in aquarium B) E.g. phosphates (usually more than enough)...