"Dan White" wrote in message
et...
By vacuuming out the
muck, am I likely removing much of the good bacteria, which then allows
fish
ammonia/nitrite to build up and give cause for a bloom?

Thanks for your response,
dwhite


This could very well be the case. Many people only vacuum half the gravel
when they do a water change. It wouldn't matter if you had a lot of
biological filtration. If you're only running one filter and it's not
carrying the majority of the biological load, then messing with the gravel,
glass, decorations, etc. could kill off enough good bacteria to get that
slight nitrite spike. Have you measured your nitrites? Ammonia is usually
the first thing to reach zero. Nitrites could take a while longer to get to
zero. I would measure your nitrites to ensure that they're at zero. I'd also
add another biological filter. Maybe a small sponger filter run off an air
pump. This will also allow for a bit of agitation and oxygen exchange in the
tank.
Tim