I could use some advice on locating a potassium additive for my plant tanks. I've been using Kent's micro nutrient product which does contain some potassium, but I'd like to be able to dose it separately from the iron and other nutrients. At this time I'm not ready to go the full PMDD route. Does anyone know of an off-the-shelf product (besides the $Amano$ one) that contains only potassium? Thanks, Ken Cova