I have been having a lot of trial and error with this and want suggestions. I am stuck on using a CO2 diffuser as an airstone for both small bubbles and and it looks nice being made out of glass. It is only a 5 gallon tank, so I bought an aPump with dual outputs...ran them backwards through a gang valve but it was not enough pressure to work. So I ordered another pump (YT-304) which is a massive quad output air pump, produced the pressure I need but was too loud on the lowest setting. I was just barely getting by with a $10 pump from the store but when I reconnected it after this large pump it no longer builds enough pressure to make the diffuser work.