Just curious though, because of the toxicity of the alum rate a whole arm length over the coagulant called chitosan, has any one attempted to use chitosan over alum. Base price of alum is probably 1/2 the cost over chitosan after shipping/handling fees. Alum will re-dissolved back into the water as stirring caused by wind or run-on. Chitosan actually retain the bound material until you can safely harvest the sunked chunks. Just something to toss into the mix.

Leo

* Knowledge and experience yield wisdom. Sharing wisdom expand the generations with crucial knowledge. Unshared wisdom is worth nothing more than rotting manure.