Too much CO2

If you have CO2 from a pressurized tank, be careful.  If you put in
too much CO2 for any reason (such as a misadjustment or equipment
failure) this could happen to you.  Two nights ago, I went to fill my
reactor (an inverted 2L coke bottle with  top removed) and to do so,
I started the flow of CO2 at about 1L/2-3minutes.  Sad to say, I
forgot to shut it off five minutes later.  As a result, it bubbled
all night.  My aquarium has a glass lid.  The space above the water
became 100% CO2 and all the fish (except a few corys) died of
asphixiation. The pH also dropped from 6.3 or so, normally, to around
5.0 but that would not have killed the SA cichlids, it was lack of
oxygen.  I don't know of a way to prevent this kind of problem except
maybe not to have a "sealed" top to your tank.  I hope this does not
happen to you.  I lost a breeding pair of Koi angels, a pair of H.
cristatus, a beautiful big SAE, some miscellaneous fish I got from my
son (large congo tetras, rainbows, etc.).  It was a pretty good tank,
took second place in SFAS last home show.  Anyway, be careful if you
use pressurized CO2.   A pH alarm might help.  Dave

Dave Gomberg, FormMaestro!      San Francisco CA USA   gomberg at wcf_com