Backyard Aquaponics
A place to discuss aquaponics

I think he means pneumatically actuated ball valves to control water flows. Pneumatically actuated diaphragm valves may be a good option too. Neither are cheap though, and you need additional (smaller solenoid air) valves to control them.
There are solenoid valves for water, but they usually need at least 2 meters of pressure and they're meant for very clean water. They're used in central heating systems and for clean water input in washing machines.

Actually, air compresses very well such that 80 gallons of air compressed to 150 PSI is about 880 gallons of air at 0 PSI. So when using a regulator to adjust output pressure down to 1-5 PSI, you do get a lot of volume out of a high pressure system.

Yea but that volume of air isn't going to serve enough air to say a fish tank that needs 1 CFM unless the compressor is running rather frequently, which most of those compressors are not really meant to do on a continuous basis. Probably more energy efficient to get an air pump of appropriate pressure and volume to deliver the right amount of air to the diffusers without needing special filters to keep the oil from getting into the fish tank.


Yea, I expect you can run air controlled water valves but the problems and expense with running high pressure air lines to all your water valves plus needing controllers etc.......... Probably easier and cheaper to just get one automated valve to control the water flow going to two indexing valves (which is what I have been doing for the past 5 years or so now.)