Not sure but given the length of time Oxydators have been around but not available in the US then few knew of them and many still don't. I have been singing the virtues of Oxydators on here for a number of years. However, most people who directly add peroxide do locally to kill a patch of GHA. An Oxydator is not designed to eliminate GHA although it does seem to help along with helping to eliminate or reduce cyno and diatoms.Interesting, I wonder if it’s not as popular because we H2O2 directly into our tanks instead.