Mike, "white" tilapia are likely a Nile or nile hybrid tilapia and will get lethargic around a 65-68* water temp and die by 55*. Duckweed and watermeal control is a real crap shoot with tilapia...it is their desire to eat it over being eaten from below..they often opt for surviving. The price is good, but the seasonal control times will be relatively short over a blue tilapia.
