Thanks Mark! I've got 6 pools with 8 filters and flow meters and only ONE of them is installed in the correct part of the pipe, 2 of them are installed on > 1' sections of pipe with 90s and/ or 45s on either end. According to the readings I take every day, I don't have enough flow to do the required 4 turnovers/ day - I was hoping that your answer would be that the flow rate would read low. (I imagine that the pools were designed to do the 6 hour turnover rate, but I can't get my hands on the blueprints [GRRR!!!] - the company that built them is an established pool co., but some things I see with our pools makes me dubious about how qualified they are to build a bird bath.)