i have a pressurized system on my 15 gallon now but will switch it our for diy when i set up my 30 gallon. i wonder if i could hook up my diy to a powerhead as a venturi diffusion and use the powerhead as a solenoid. i will probably use it with a timer with the lights.
Sure you can do that. Best is to let the powerhead suck the bubbles into the inlet, and have them just escape to the surface while the ph is off. That way the pump doesn't get airlocked while it is off.
A real solenoid is worth it though... saves CO2, and turning off the powerhead at night reduces overall circulation in your tank.
i know a real solenoid would work best. but i don't think my parents would get me another set of presurrized co2. the powerhead i have has a venturi style build on so that there isnt any airlock that may damage the motor.