If you go to that referenced post, read Chas response. When he tried Eco One, he did so with updates to Doc's forum, specifically to Vermonter who did some testing of Chas water for bacteria, etc. If I recall correctly, the results were very nice water, but without addition of chlorine, there were substantial numbers of bugs over and above what a normal chlorine spa would contain.
IMO, it is a nice product if used with a little chlorine. I don't even think you have to shock with it. I would have tried it already except for the claims of having to rinse the filters weekly which to me is the worse job in hot tub ownership.
A similar product is the Natural which can be purchased from Doc. He has some good info on the product at his site. There are also some Natural users who post there who swear by the product.
BTW, these enzymes are different than products such as Leisure Time Enzyme (Scum Gon) or Spa Perfect.
