Pressurized CO2 w/ pH Meter: Turn off at night or not?

[WhiteCloud]

I will be setting up my new Pressurized CO2 system with pH controller next week. My question is:

Do I set my CO2 system on a Timer so it goes off at night when plants are not using CO2 or not?

I do not want to have huge pH fluctuations, but I do not want to overdose my fish with CO2 either..both can be dangerous to the fish.

My gut feeling is to keep the CO2 on all the time...and perhaps have an airstone on a timer that will go on at night. This is do several things:

1. Provide O2 to fish and plants (as plants use O2 when not producing CO2)
2. Cause some surface agitation to get some of the CO2 out of the water so it will not accumulate while plants do not need it.


Any thoughts?

Thanks

 

[malkore]

I don't think you understand the purpose of the pH controller. It's purpose is to monitor your pH, and when it hits the pH you've specified as the low end, it turns off the CO2 flow.
Therefore, you do not need a timer and you should not use an airstone at night.

I'll also add that many people run CO2 24/7 without a pH controller and have no problems. I'm one of these people. My dKh is 8, so my CO2 never gets above 30ppm and never below 20ppm due to the amount of buffering. Its the people with 3 dKh that should consider pH controllers, as they'll have a much wider range than my tank.

 

[Guest]

Set your PH controller to the desired PH and forget about it. Thats what the controller is designed to do, keep a stable constant PH level.

Timers are for cheap people like myself, that don't want to spend the money on a controller. (A controller is on my wish list)

As a side note. Be aware of PH swings during WC's. In example......Say your tap PH is 7.8 and you adjust your PH down to say 7, useing the controller. When you do WC's your going to have PH swings that can harm, stress, even kill fish.

Just something to keep in mind. HTH

Edit: Malkore posted the same time I did LOL.

My timer is set to turn off approx. 30 mins before lights out. The CO2 timer then turns on about 45 min. before the lights turn on in the morning. AS mentioned, KH is important. My KH is a rock solid 5KH, so PH flucuation is to terribly bad.

 

[malkore]

Hehe, Mojo means "...so pH fluctuation is NOT too terribly bad"

 

[WhiteCloud]

Thanks for the replies!

My water currently has:
pH: 7.8
KH: 6
GH: 6

I was thinking about setting the pH controller to 7.2 or so.

Mojo...I had not though about water changes....what do you recommended with that? I use a Python and take about 10-15% water out weekly. Should I just put the water back in the tank more slowly? I would hate to use chemicals to bring the pH down before adding water back. Does 10-20% really affect the overall pH that much?

...or pehaps I should replace water from water changes with RO/DI water that I will be setting up soon for my Reef tank....but then I would not have any buffering effects from the RO/DI...oh my....this is getting a bit confusing.

WC

 

[BrianNY]

With a KH of 6 you're not going to have alot to worry about regarding swings of pH. You can do as much as 50% with a pH of 7.2 in your tank and 7.8 in your tap. It's the downward pH swings that really stress fish.

 

[luiscuna]

I've got a pH meter running for 2 years, and it keeps operating 24/24 hours except for a brief period ( 1 hour) for calibrating and cleaning 1 year ago. After you put it working, you'll have instant and continuous access to your aquarium pH. The system is designed to keep the pH shift as small as possible. You can monitor the pH shift during water changes, so you don´t have to rely on pre-made values but instead find out the limits for your tank. You'll notice the daily shift- related to CO2 consumption by plants.
About the problem of O2 and CO2: CO2 it´s 20 times more diffusible than O2, so at all times and providing that the surface moves ( action of filter) CO2 will go out. Another tip: you be measuring your pH with two digits (ie: 7,23; 7,28 ) much more accurate than usual readings, so don´t be stressed if your pH swings from 7,20 to 7,31 - with reagent, you probably wouldn´t notice it. Good luck!!