re: substrate fertilizers

---------- Forwarded message ----------
From: CCSTRAND at aol_com
Date: Sun, 27 Oct 1996 22:16:51 -0500
To: aquatic-plants at actwin_com
Subject: Re: substrate fertilizers

 I am in the process of setting up a habitat aquarium with a substrate
heating system.  I cleaned and put approx. 1" of 1/4" pea gravel over the PVC
heating pipes and then added a mixture of "Sera Floredepot" fertilizer and
some laterite red clay, as a fertilizer base for the plants.  then topped it
with 1 1/2" fine gravel.
 My problem is now that I'm filling the tank (240 gal.), I have a problem
with the laterite leaching from the gravel into the tank, creating what
appears to one heck of a large "bloody mary" effect.  I'm using a wet/dry
trickle filter made using a 29gal. tank...with a sponge prefilter...which of
course does nothing to clear the water.
 The laterite particulate is so fine it doesn't get filtered out.  After 2
days I tried filling two bio bags with activated carbon and placed 1 each
under the intake pvc pipes in the drip tray.  The wet/dry filter is equipped
with two RIO 2500 pumps that each return about 500-600 gph....still no luck!
  Today I did 3 complete water changes which definetely improved things, for
awhile.  But now after several hours it appears that the laterite is again
leaching into the tank. 
 Any suggestions?  Do you think in time the charcoal will clear the water?  I
would like to think that the leaching will eventually slow and stop, but
havent had any experience is this area,  I also feel that the substrate
heated system is working and the resulting convection currents in the gravel
is helping to move the water thru the gravel and laterite.  I dont't know
anyone that has experience with this type system but would appreciate some
help. >>