pH Controller

Allwissend

Super Moderator
Staff member
Moderator
Lifetime Member
Jun 20, 2016
871
382
63
www.intuitiveaqua.net
depends on what you want to do with it. If your main concern is keeping a good CO2 level when the lights are on then5 you can shut it off at night and open it a few hours (or whatever time it takes for your system to reach the targeted pH) before the lights are on. In this way you only inject CO2 when the plants need it the most.
 

Bald_noggin

New Member
Jul 9, 2019
6
5
3
53
Canberra, Australia
I just recently begun turning off the CO2 of a night time as it is a bit of a waste if it’s not going to be used by the plants at night plus, I tend to go though a fair bit of it with the size of my tank as my reactor is not quite running optimally for dissolution of the CO2. New reactor under construction at this very moment.

Technically, I don’t turn it off but set the CO2 system for a pH of 7 and then set it back to 6.45 two hours before the lights begin to ramp up in brightness. It takes about 6.5 hours to go from 6.45 to 7 and 2.2 hours to go from 7 to 6.54.
 

Mmiller2001

New Member
Mar 5, 2022
7
5
3
USA
Okay, thank you both. My thinking was the pH would stay low enough to keep it triggered off over night. This didn't happen so it makes sense to turn it off over night.

Now I'm wondering this. Should I increase the injection rate to hit my target faster, or just use what I did before and have a slower all day rate?
 

Allwissend

Super Moderator
Staff member
Moderator
Lifetime Member
Jun 20, 2016
871
382
63
www.intuitiveaqua.net
Depends ... fav. word :) If you are using a reactor I would suggest keeping the rate of injection slow as this avoids over-injection of CO2. In other words, if you inject CO2 at a very high rate it's possible to fill up the reactor by the time the PH drops enough to close the CO2 injection. Sure the injection stopped but there is still a lot of CO2 in the reactor messing up with your stable value and potentially putting fish in danger. If you are using a diffuser I would still prefer slower as I don't want to hear the solenoid going on, off several times an hour.

I prefer to adjust the injection rate to the point the pH controller stays open on most of the time, mainly acting as a safety mechanism
 

Bald_noggin

New Member
Jul 9, 2019
6
5
3
53
Canberra, Australia
I agree with you Allwissend, regardless of method of injection, go slow.

I set mine for what is required to hit my target and a bit more. If your bubble rate isn’t high enough, you won’t reach your target. Trick is to creep up on it slowly until you reach your desired level. System I built checks the pH every 5 minutes and switches on/off +/- .02 of my set target of 6.45. When first set up, the pH would not go all the way down so, open the needle valve a touch more and repeat until the system kicks in and starts taking control.

Here’s a typical day of CO2 injection.
E2A4CEC9-C1DE-48A7-BE27-0C17B1C72C1B.jpeg
 
Last edited: