Ok, so this thread is a little old, but I thought it better to continue the thread rather than start a new one.

I've looked at those controllers on ebay for about $75. The have the plugs for a CO2 tank. Could that plug just be used with a very small water pump, maybe a relay, and a reservoir of premixed acid? It seems like a pretty cheap way to do it.

I just don't wanna spend money to buy one before I know it'll work.