• Get the NEW AquariaCentral iOS app --> http://itunes.apple.com/app/id1227181058 // Android version will be out soon!

CO2 valves


Registered Member
Hello - I am new to this forum. I've had a small aquarium for awhile, but am upgrading it to a larger one for more fish/plants. I will be having a CO2 line and have a few questions on valves. Are most people using solenoid valves on timers?


AC Members
Yes, I believe everyone in my plant club uses a solenoid & timer combo. I have them but haven't "pulled the trigger" on using co2 just yet.


Josh Holloway--Be mine!!!
I have been using a solenoid valve in my 2 tanks, for CO2, now for over 10-15 years.
I dint know anyone who does not use a solenoid, either with a diner or with a pH controller


AC Members
LOL, dougall.

Many start co2 at most an hour before lights come on & off just about lights off, whatever those times are for your tank. It won't matter, you can even split the time between am & later pm if that works better for your schedule of viewing times. CO2 at "night" is a waste of gas & might be a hazard to your fish if it's cranked up high.
Remember that while lights are out, plants will not photosynthesize, and will respire, releasing CO2 back into the aquarium, adding CO2 that will not be used will lead to too much CO2 in the aquarium... which is not a good thing.

Trying to close vales at night, and reopen in the AM is way too much work, and also can lead to inconsistent CO2 levels in the aquarium, this can cause Black Beard algae among other things.

Most Regulators will come with a solenoid, or it can be maybe $10 to buy one, add a $5 timer too.. it's well worth the investment.


Global Moderator
Staff member