ps i am using 6 in airstones in 6in baskets with white sterilized vermiculite for fish tanks.Someone metioned dive gas,i believe the o2 from the machine is 90 percent.and the {patient] has plenty of e sized oxygen tanks so the machine is only used when im running it lol.i built on the bubbler idea from the grow bible and using purer than atmospheric air seemed the way to go.within the next two weeks ill start identical clones in a controlled inviroment.1 with an air pump one on o2,same nutrient solution.there may be a few bugs as far as litres per minute but it will be close.any ideas???????peace