M
Marcel G
Guest
Hi all,
recently I do some pH monitoring in my tanks with CO2, and have some questions which I can't find answer for.
I have read some [non-scientific] articles where the authors say that rapid pH changes cause stress to fish. When I measured the pH in my tank during 24 hours period, I have find out that the pH droped by 1 point (from 7.4 to 6.4 in my first tank, or from 8.0 to 6.9 in my second tank) in just 2 hours after I turn the CO2 system on/off ! Is it true that these shifts in pH could cause stress to fish/shrimps? Does anyone know some guaranteed info on this, or link to scientific study?
Also some people don't turn their CO2 supply off at night to keep the pH relatively constant (to avoid these dramatic pH swings). But this way they have permanently high CO2 levels (although they keep them a little lower => say around 15-20 mg/L). Many authors state concentrations above 20-30 mg/L as dengerous for fish (e.g. Christel Kasselmann, Horst and Kipper, Ines Scheurmann, George Booth, Chuck Gadd).
Both seems to pose some problems or risks for fish and shrimps:
1) Permanently high levels of CO2 could cause acute or even chronic stress to fish.
2) Dramatic pH swings can cause stress or even death to fish.
Are both statements true?
And if so, what is worse?
Is it better to have permanently high CO2 level with stable [non shifting] pH, or to have high CO2 level at day, and low at nigh ... but with dramatic pH swings?
Marcel
recently I do some pH monitoring in my tanks with CO2, and have some questions which I can't find answer for.
I have read some [non-scientific] articles where the authors say that rapid pH changes cause stress to fish. When I measured the pH in my tank during 24 hours period, I have find out that the pH droped by 1 point (from 7.4 to 6.4 in my first tank, or from 8.0 to 6.9 in my second tank) in just 2 hours after I turn the CO2 system on/off ! Is it true that these shifts in pH could cause stress to fish/shrimps? Does anyone know some guaranteed info on this, or link to scientific study?
Also some people don't turn their CO2 supply off at night to keep the pH relatively constant (to avoid these dramatic pH swings). But this way they have permanently high CO2 levels (although they keep them a little lower => say around 15-20 mg/L). Many authors state concentrations above 20-30 mg/L as dengerous for fish (e.g. Christel Kasselmann, Horst and Kipper, Ines Scheurmann, George Booth, Chuck Gadd).
Both seems to pose some problems or risks for fish and shrimps:
1) Permanently high levels of CO2 could cause acute or even chronic stress to fish.
2) Dramatic pH swings can cause stress or even death to fish.
Are both statements true?
And if so, what is worse?
Is it better to have permanently high CO2 level with stable [non shifting] pH, or to have high CO2 level at day, and low at nigh ... but with dramatic pH swings?
Marcel