"If the Substrate is the source of nutrition and it is not replenished, its performance can deteriorate." I agree! Troy you mentioned that there are some plants who rely on substrate nutrition - could you name them? Did you actually try to grow them using full water fertilization, after substrate has deteriorated and just couldn't grow them well? Has anybody analyzed the amano's substrates? If it's not the CEC then it's the rich nutrition right? And I guess initial ammonium levels that boost plant growth. But we could have the same magic by adding very moderate amounts of ammonium into the water column - no? Same explosive growth - same algae risk as with powersand/aquasoil - no? Aviel. _______________________________________________ AGA-Member mailing list AGA-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/aga-member