I had another Purigen question. I just started using this about a week ago in my 50 gallon tank. I picked up 250 ml to try and the Sechem Bag to put it in. I used a quarter of the 250ml bottle which should give me more than the suggested dose of 1 ml per gallon. Can't say that I am yet seeing the amazing results everyone claims for this product. Any suggestions as to what constitutes a proper dose? It is expensive enough that it would be nice to find a good dose threshold instead of simply overdoing it.