bubbles of H2SO4 in gravel

>> line".  Beneath the gravel there is a dark algae growing which I can
>> see looking though the glass on the side where air bubbles also form in
>> the gravel...should I worry about this?
>Hmm, those bubbles could be poisonous sulfide gases (H2SO4) which
>are formed by anaerobic decomposition of excess organics in your

I've been lurking here for quite awhile and have enjoyed this discussion
group immensely.  Now finally I have come across something to which I can
contribute.  Sulfide gas (H2S) comes from decaying organic matter
containing sulfur and it is true that it is poisonous.  H2SO4, however, is
sulfuric acid and is a liquid at room temp.  I looked up hydrogen sulfide
in the Merck Index (a reference book for chemistry) and it said it smelled
like rotten eggs.  It also said that it would react with the dissolved
oxygen in water to form elemental sulfur.  This information may not help
you identify the bubbles but maybe it will clear up some confusion.

Cindy  (Cynthia.T.Cua.2 at nd_edu)
South Bend, Indiana