Sounds far more likely that the bubbles are oxygen, because your tank is
working well. The roots push out considerable quantities of O2, and if the
water it saturated with O2 then it will form bubbles - just as with pearling
above the substrate on plant leaves. One reason why plants are good, as they
*prevent* the formation of anaerobic areas in the substrate.

Sounds like the tank is working fine to me.

Colin

"SteveG" wrote in message
...
redled,

Well, the tank doesn't smell like rotten eggs. (Whew!) I will post on
this
newsgroup on any results I get.

Thank you!

Steve G