is pH swing normal when using CO2 solenoid regulator?

[chua]

hi

i am presently using a CO2 solenoid regulator.

But the ph swing is about 0.6.
from 6.4 before lights off to 7.0 the next day just before lights on.

Is it normal?

It is because plants and fishes are respiring at night. This means that they should add on to the present CO2 resulting in a further drop in the pH level.

If so,
what is the reasons for the increase in pH or the drop in CO2 level during the night?

Thks for the help.

[IUnknown]

I have never used an automatic system, but I thought they just control for to much Co2. For example you can set it so that the pH doesn't go below 6.7. Co2 should be high in the morning and low at night. So thats opposite to whats going on in your tank. Plants give off Co2 at night and the pH goes down. Plants use Co2 during the day and pH goes up. You could set it up so that the controller allows for less of a pH swing by increasing your bubble rate.

[altum]

[quote:5a81977bbb="chua"]hi

i am presently using a CO2 solenoid regulator.

But the ph swing is about 0.6.
from 6.4 before lights off to 7.0 the next day just before lights on.

Is it normal?

It is because plants and fishes are respiring at night. This means that they should add on to the present CO2 resulting in a further drop in the pH level.

If so,
what is the reasons for the increase in pH or the drop in CO2 level during the night?

Thks for the help.[/quote:5a81977bbb]

If you are using a solenoid system, it means that the CO2 is cut
off at night. So naturally, with the CO2 dissipating at night and no
injection, the PH will go up by morning. Respiration by plants and fishes
should not contribute much CO2 to the tank, otherwise we would
not need a CO2 system.

The swing in PH is normal if you are using a solenoid system. If
you want constant PH, you can always add a PH controller to your
CO2 system.

Some of my tanks run without a solenoid, the CO2 is on 24 hrs
a day. So far there are no ill effects on the fishes. Neither were
there in a solenoid system.

Hope that explains your questions.

Cheers
Chong

[chua]

Thks for the reply.

But why will CO2 dissipate away?

[altum]

CO2 dissipates due to gas exchanges that occurs normally.

Hope that helps.

Cheers
Chong

[chua]

oic.

People using solenoid can share your pH swing.

I will start first.
From 6.4 (with CO2 with lights on) to 7.0 (without CO2 just before lights on).

So my pH swing is 0.6.

chong can share yours too.

Thks.