I need to add Nitrate and probably Potassium to my tank in order to get the
plants to grow and algae to die off (hopefully). My Nitrates are 0 (when I
add Flora Grow or other substance it increases slightly, when I perform a
water change it increases a lot) not long after (in days) its back to 0 and
there seems to be far more hair algae (some brush is appearing as well)
covering all my plants. I inject CO2 as well. Its bloody frustrating.

So apart from the 3% potassium that the flora grow will put in (which is
expensive as well) - I have purchased some Sulphate of Potash......for
garden usage. It says on the packet that it has 49-50% K2O - but it doesn't
state other chemicals. It's very white and very fine grained and looks like
cocaine (as if I would spot it even if it were put in front of me - lol).
Anyway if I catch the fish using straws and floating around the living room,
then I know something has gone horribly wrong - lol lol.

My question is - is this stuff suitable for an aquarium when sufficiently
diluted and where can I find the maths for diluting it properly. I live in
the UK and the product is http://www.gemgardening.co.uk/prodlist.asp?val=veg
however, has anyone else used this at all. I would hate to kill off all the
fish in an experiment to get rid of algae. I have read, on the Krib that
about 3/4 teaspoon for my 250L (66G) tank should be enough per week. But I
would like to make up a solution so that it can be added easily.

Does anyone know what I can buy for the KNO3 please....In the UK.....

Thanks in advance

Martin