Re: Iron content of clay & trace minerals

> From: Earle Hamilton <ehami at sunny_ncmc.cc.mi.us>
> Subject: Laterite - the whole story

Thank you for a very informative bit Earle. With a little arithmetic
we can see that clay with 7% Fe2O3 used 1:10 with your gravel would
mean 1.1 ounces of iron oxide added for every 10 pounds of gravel or
in metric 68 gm / 10 kg. Iron oxide is easy to synthesize ;-)
either put a pound or so of super-fine steel wool in water for a few
days or *burn* it. If you choose the more conservative concentration
(1/2 lb laterite / 25 gal) you would use 1/2 oz of Fe2O3 for 25
gallon aquarium or 14 gm for 100 liters. However, I think we are
better off not adding iron oxide to the substrate. Instead use
clay, vermiculite or earthworm castings and the "Chelated Trace
Element Mix" mentioned by Ed Tomlinson!!! Now with this stuff, you
need to be careful of the concentration because Fe is used up but
there can still be a significant concentration in the tank and it
is easy to overdose iron and make your fish and snails very sick or
dead. Assume that you desire .1 ppm Fe in 100 liters (25 gal).
This would require .14 gm of the "Chelated Trace Element Mix" and
its very difficult to measure this small amount. If you go for
1 ppm Fe, you have 1.4 gm. Even this is hard to measure. You can
mix up a larger batch, say 1 liter and then use 10 ml at a time to
get a more accurate dose. You'll want an accurate Iron test kit
to get an idea of your consumption in order to establish the amount
to add each week (or day). Somebody should double check my math.

 - Steve