Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!zaphod.mps.ohio-state.edu!usc!snorkelwacker!husc6!m2c!jjmhome!cpoint!alien
From: alien@cpoint.UUCP (Alien Wells)
Newsgroups: alt.aquaria
Subject: Re: Live Rock Followup
Message-ID: <3526@cpoint.UUCP>
Date: 16 Jan 90 14:09:45 GMT
References: <1990Jan16.003429.22055@agate.berkeley.edu>
Reply-To: alien@cpoint.UUCP (Alien Wells)
Distribution: usa
Organization: Clearpoint Research Corp., Hopkinton Mass.
Lines: 55

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
--------|     decvax!frog!cpoint!alien      bu-cs!mirror!frog!cpoint!alien