Backwash your filter when the pressure reaches 10psi over the “clean reading” to obtain the best filtering capabilities. If your pool is dirty, green or cloudy, backwashing may be a frequent task. This is because the filter is doing its job of pulling out the problem causing contaminants. Remember, every pool is different. Your pressure readings will be different than your neighbors. Also, if you have a variable speed pump, each speed will result in a different PSI reading on the gauge. Pick one speed to judge the pressure readings to determine when it is time to backwash.

Here are some general instructions that may help refresh your memory.

Overview for backwashing a DE filter with a multiport valve:

Overview for backwashing a DE filter with a push/pull valve: