I think most will agree that this is a definite agree to disagree topic on TFP. But here it goes.....There are some members who, for whatever reason, use TFP method for getting rid of mustard algae (the dreaded "it could be pollen, dirt, or sand") but it constantly reappears. I will up front admit to being one of those members. I have certain fixtures that I cannot thoroughly brush. I spent from May 8, 2019 to the end of July doing everything the book. It was a battle I could not win. So I reluctantly researched elsewhere and finally came up with something that works for me. I think it would be nice to have somewhere in the forums for us to go and get advice or share what has worked or not worked for us. We wouldn't have become members if we didn't want to be full fledged TFP, but as with everything, there is always an exception that takes people outside of the box.