Another point is that by putting nutrients in the substrate you can use those which are NOT as soluble in water. Plants with roots can still utilize these nutrients but they are less available to algae because they haven't dissolved yet. Like putting bonemeal under your onions. Steev "Hess, Clay A" wrote: > Paul, > > Yes, I know. My point was that they will leak into the water no matter how > deep one places them in the substrate. > > Clay _______________________________________________ GSAS-Member mailing list GSAS-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/gsas-member