I run my pump 27/7, but not at very high speed. At night I run it at between 25 and 35 GPM (depending on my mood). During the day I run it at 1,100 RPM which provides enough flow to go through my small solar heater using only about 100 watts of power (I have time of day electric). As for testing, unless it does not taste right too me, I probably only test it about once every two or three weeks. I use two or three pucks a week and maybe two or three gallons of bleach. I find the mix of the two holds the pH very steady, while pucks tend to drop it and bleach tends to raise it.