I have been dosing EI using the excellent NutriCalc recommended by Matt (thanks Matt ) without any issues except for some minor hair algae on my vallis but i have noticed that in a lot of EI articles i have read lately there is no mention of Magnesium Sulphate in the dosing regime, why are we dosing this? is this just for the Mg? i'm not likely to change what i'm dosing because it's working so well. I just want to be sure i understand why i'm doing it. :? Incidently, if you need to clean Hair Algae off of your plants find some goldfish! i tranfered mine to my 8 year old sons 120 goldfish setup and they cleaned a huge bunch of it in about an hour! they seem to love the stuff!