alien@cpoint.UUCP (Alien Wells) (01/16/90)
In article <1990Jan16.003429.22055@agate.berkeley.edu> markh@sag4.ssl.berkeley.edu () writes:
%Thanks to the several of you who so quickly sent messages about live rock.
%Although some of it was mildly contradictory, I think I can sort it all
%out. There's one point I'd like further feedback on, however.
%
%alien@cpoint.UUCP (Alien Wells) writes,
%
%>Let me get this straight. You had a working tank with a few fish and a UGF.
%>You then added a trickle filter, and you plan to disconnect the UGF as the
%>trickle filter gets established? Sounds risky to me ... make sure you are
%>very gradual about it, slowly decreasing the flow through the UGF until it
%>isn't doing anything ...
%
% I think it would be a BAD idea to slowly reduce the flow through
%a UGF. Seems to me you could end up with a massive amount of anaerobic
%activity down there. I plan to keep the UGF running full strength (2
%powerheads) for 4-6 weeks, then disconnect one power head and immediately
%get 1/2 the gravel and one UGF plate out of the tank, then repeat for
%the other UGF plate some number of days later. This, incidentally, is the
%procedure suggested by the trickle filter mfgr.
After reading your posting a couple of times and spending some time thinking
about it, I have a few comments.
First, I think that you are probably right that cutting down all the way to
zero on the UGF flow could be bad. However, I also think that going 'cold
turkey' and yanking the UGF 50% at a time is very risky.
I would still gradually cut down the flow (though perhaps only to 1/4 or
normal flow) before pulling the UGF (50% at a time is a good idea).
% I know, it sort of seems as if there won't be ANY bacteria growing
%in the trickle filter for the first 4-6 weeks, because the UGF will be
%breaking down all the ammonia and nitrites. But I don't really buy that -
%I suspect that nearly EVERY surface in a tank has those bacteria on it.
%The ones that colonize the trickle will presumably have an advantage over
%their established cousins in the UGF, because of the high oxygen content
%in the trickle, and the high water turnover rate. In equilibrium,
%(4-6 weeks from now, maybe) with all filters running at full blast, some
%large percentage of the ammonia and nitrites produced will be broken down
%in the trickle, and only a small fraction in the UGF, at which time it's
%safe to remove the UGF. Or at least part of it, to shift more of the
%total to the trickle.
You will definitely get a build up of bacteria in the trickle filter. The
question is how much. The 4-6 week time frame is reasonable, the only real
change I would recommend is to gradually (say 1x/week) cut the flow through
the UGF during that 4-6 week timeframe. This will make sure that the vast
majority of the bacteria are in the trickle filter while still maintaining
enough flow to keep your UGF from going anaerobic.
--
--------| With Altzheimer's Disease, every day is a new day!
Alien | - Earl McKennon
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