I have a 1.5 HP Pentair Dynamo High Performance with a Fiber Glass (sand) filter. Under normal operating conditions (pool clean, recently backwashed), my PSI sits at about 15. At 15 PSI the return jet is powerful enough to where my hand cannot easily plug it (it pushed my hand to a side or sprays up out of the water). It creates a pretty decent whirlpool. Once it reaches 19 PSI, I can easily plug it with my hand but still has enough power to resist. Then at 20 PSI, its very weak with almost no flow. The general tip is to backwash once you are 10 PSI over your normal operating pressure. I don't even think I could get past 20 PSI ever and even if I did the pool would probably be at a stand still.
So my question is: Is there a general rule of thumb to determine if your flow is so low that its negativly impacting the flirtation/circulation of the pool? During the begininig of the season (now), it can easily jump to 19 PSI after a few hours of back washing (pool extra dirty this year, on day 3 of SLAM). I don't want to backwash to often because to me it seem like sand filters are not as good at filtering right after a back wash and need a little be of debre (or DE) to help catch the smaller stuff.
So my question is: Is there a general rule of thumb to determine if your flow is so low that its negativly impacting the flirtation/circulation of the pool? During the begininig of the season (now), it can easily jump to 19 PSI after a few hours of back washing (pool extra dirty this year, on day 3 of SLAM). I don't want to backwash to often because to me it seem like sand filters are not as good at filtering right after a back wash and need a little be of debre (or DE) to help catch the smaller stuff.