Still nothing from the OP. Not knocking the idea of using this koi clay at all, (I know nothing about it personally) but if they have a UV as good as they say, why on earth isn't that doing its job, clumping it together and letting the filter seive it all out whatever the actual cause is of the greenwater? Something is really wrong here and the reason for the green water still isn't clear (!) and needs to be addressed obviously, but unless we hear from them we'll just have to wait.......and wait........