Yeah, we tried 70+ pounds per acre and got our butts kicked. It took cutrine, tilapia and microbes, the next year, to handle that one. The trick with FA is getting on it immediately and not letting it get ahead of you. If you do, it becomes an infestation and nothing works. As it dies back, the dying stuff becomes fertilization for the next wave.
Phil, that was at Aledo and the alkalinity was about like yours.