What a week, I have a friend that is looking to convert his swimming pool to AP.    It is already green with algae and he had this idea.    the low end he was going to make the grow bed, then drain it down to have a large deep end.   Then run the water up from the deep end to flood the gravel.    Hmm the more I think of it I bet he could have floating rafts on the one end which would be MUCH easi…