Filtration was antibiotic

["Adam N." <adam at xhaos_org>]

Bob wrote with regards to bacteria kill off via antibiotic:

If you've got water movement in your tank you have filtration, biologically
speaking.  Every surface in the tank is no doubt colonized and in the o2
saturated environment of a high light planted tank, which I assume you have
since you are saying that you are running filterless, unless you have no
fish, it's probably pretty darned effective.

You may not have mechanical filtration but you assuredly have biological.
If you are running a substrate heater you also have a chemical filter
running if there is some kind of clay in there.

It may not be mechanical filtration but things are being removed from or
modified in the water column via contact with media

Adam