I THINK the fact that your tanks are prone to bouts of BGA probably says
something about your tanks. ? BGA is usually caused by unstable conditions
(frequent massive water changes), compacted substrate and oxygen deficiency,
and/or nitrate-rich tapwater.

At some point, the maracyn will kill off the nitrifying bacteria in your
tanks, and that's a bad thing. If you think you may have already
destabilized your tanks, dose with A.C.T. by Mardel.

The best permanent solution is to plant lots of Sagittaria, which excels at
removing nitrogenous waste from the water, and to keep your thermostat
turned DOWN below 75º to inhibit BGA (I keep mine at 72º to 74º at all
times). Use MTS to aerate your substrate. Ramshorn snails are reputed to
eat BGA (although I can't say that MINE do).

Good luck. I lived with BGA in one of my tanks for nearly a year before I
finally managed to eradicate it.

SLEngst wrote in message
...
I had forms of BGA show up in 3 planted tanks. I treated all three for 5
days
with the 1/2 dose of maracyn needed for fish fungus or whatever, as
suggested
in an article in the KRIB. It came back in two tanks. I treated them
both for
7 days with full doses of maracyn. A week later it now seems to be
reappearing
in one of those two tanks. First clue is - even my prefilter media is
starting
to "pearl", as are above substrate roots, etc.

Do I do some huge water changes, again? and go for 10 days on the maracyn?
I
just did a virtual 90% water change on that tank less than a week ago.
How
much of this (maracyn) can the fish take?

Thanks in advance,
Sharon Engstrom