loz, all that stuff can be scary, just be careful and read, read, read! the tablets are not safe for pond plants, so i have never used them. i DO use the liquid algaefix stuff. i just ordered some from foster/smith catalog, the brand is pondcare. i got the 64oz. size. 1 teaspoon for every 50 gallons-every 3 days until clear, then once a week FOREVER in warm weather! it does great as long as you keep the water moving with a good pump. i love the stuff!