I had a mix of Flourite and gravel. I just switched out that substrate last Friday to Black Flourite. I had been wanting to get rid of the Flourite/gravel mix for some time and with all the staghorn on it I thought that maybe by cleaning out everything with the staghorn on it, I might be able to get rid of it. I scrubbed the dw really well that had it on it also. So, I guess we'll see if it comes back or not.