"John Worfin" wrote in message
. net...
Has anyone attempted to remove and replace portions of the gravel of their
tank, without first tearing the tank down?

Just did this very task recently. I changed my 46g Bow Front from a South
American planted tank to an African Rift lake design. The answer is very
slowly over a long period of time. A month actually.

I started by siphoning out a little of the gravel with every water change.
I do water changes of 10% weekly. The tank contained about 30 lbs. (US) of
gravel and Flourite (mixed 50/50). Each change event removed 1 to 1.5 lbs
of gravel. This gravel was put aside for use in another tank. I then
installed an aragonite substrate (thoroughly washed) for the new Rift tank.
I also added about 30 lbs of limestone rock and a piece of bog wood (yea, I
know about the acidic trait of the wood). pH went from about 6.8 to 8.2.
The fish that were in the tank were one Synodontis eupterus and 5
Tanichthys albonubes (White Cloud Mountain Minnows). Filtration is supplied
by 2 Emperor 280 filters and one Hagan 660 powerhead w/ sponge. No problems
in the tank and the fish never got overly stressed (other than with a normal
water change). I ended up leaving the Minnows in as dithers as they seemed
to accept the new water conditions well enough.

The tank now, additionally, houses 2 Labidochromis caeruleus and 2
Aulonocara jacobfreibergi eureka. I also left a population of Ramshorn
snails in there as well, which the L. caeruleus seem to be investigating as
a possible food source (or at the least as a potential for late night
entertainment). Some day the minnows will be moved, as soon as I have the
asian tank I'm trying to get set up finished. I am constructing a Net
Max-ish background for the asian tank which is looking pretty good (despite
a couple errors).

No blooms or deaths as I believe the bio-wheels and the sponge maintained
the bio load for the tank during transition. The pH took about 4 days
(according to log) to increase to the now stable level of 8.2. Time length
was probably a significant contributor to success. I have found that
patience is a real virtue in this hobby. Hope that helps.

Marlin