Is your filter pressure running low or does your pump motor sound strained? Was your pool pressure fine a week or so ago? Do you have an automatic floor vacuum that is barely moving on the pool floor? If you answered “Yes” to any or all of these questions, your pump impeller could be clogged with debris. This especially holds true if you have palm trees around your pool as the fine hairs of the palms tend to clog things up. The location of the pool pump impeller is shown in this cut-away of a pump.
If you have a floor vacuum, check to see if any of the hoses are cracked. To do this – with the pump running – pull the hoses above the water one by one and bend them back and forth. If you hear air coming from any hose, throw it out.
If these efforts have not increased your filter pressure, you now need to look at a possible clogged impeller. Collect a coat hanger and a pair of pliers
Once you are done, put the pump basket back and with a garden hose, fill the housing with water in order to prime the pump correctly. Replace the pump lid.
If your pressure is still low, have a professional look at your pool as there could very well be something else wrong.