pH increase after water change

[barmby]

Hi,

In my 5ft tank, the pH measures 6.7 before water change. However, pH becomes 7.0! after water change. Nothing has been adjusted. Why is it so?

It bothers me because this shows that my ppm level of CO2 is not sufficient after water change! ! But why?

[PeterGwee]

[quote:db5805b1a7="Barmby"]In my 5ft tank, the pH measures 6.7 before water change. However, pH becomes 7.0! after water change. Nothing has been adjusted. Why is it so?[/quote:db5805b1a7]

You replaced the CO2 enriched water with water of ambient CO2 level (3-4ppm max)...the pH is going to rise due to less acid (CO2) acting on the water. Its really not a big deal..it always happens week in week out for folks.

[quote:db5805b1a7="Barmby"]It bothers me because this shows that my ppm level of CO2 is not sufficient after water change! ! But why?[/quote:db5805b1a7]

A good CO2 reactor is going to return the CO2 level of tank back to its optimal range within an hour or so. Not a big issue unless you have a lousy reactor or poor tank circulation which is critical for your big tank.

Regards
Peter Gwee

[barmby]

A good CO2 reactor is going to return the CO2 level of tank back to its optimal range within an hour or so. Not a big issue unless you have a lousy reactor or poor tank circulation which is critical for your big tank.

Reactor may not be an issue here because CO2 output got to be doubled or so after water-change in order to replace the lost CO2 (ppm).

I believe within one hour, its not going to return the CO2 to its optimal range if the CO2 output (bps) is still the same..

What do ya think?