I have been told by a great many people that I don't need a RO/DI filter in Loveland, in fact a call to my LFS (D&G) resulted in the information that they don't sell or use ro/di water. I have not called Great White, but have heard that they do not use it either. I have been fighting green hair algae for a while and figure it can't hurt. Does anybody know where I can buy some on a regular basis?