Has anyone used this? I was using Tetra Aquasafe Plus, but I ran out and this looked to be about the same. I bought it and used it for one water change (had a little Aquasafe left wanted to make sure it worked) I have a 20 Gallon and 1 ml treats 20 gallons, the whole bottle treats 9000 plus gallons. Thats right 9 thousand plus gallons.