Swimming pool filter problems are never fun, but before you go shelling out big bucks to have a professional fix it, check out our handy guide to troubleshooting pool filter issues. Here, we break down common pool filter problems and how to fix them.

Pool Filter Is Leaking Water Around the Clamp

In a DE filter (diatomaceous earth filter) or cartridge filter, the top and bottom halves of the filter tank are held together with a clamp. Leakage around this clamp means there is not a good seal. To fix the problem, first turn off the pool pump. Drain the water from the filter tank and remove the clamp band. Take off the o-ring and wipe it clean, and also clean the inside rim of the tank where the o-ring sits. Inspect the o-ring for damage. If it has cracking, dry rot, or is no longer round, replace it with a new o-ring. If there is no damage, lubricate it with Teflon-based pool lube and return it to the tank. Replace the top half of the tank and put the clamp band back on, making sure to tighten the nut completely. 

Pool Filter Is Leaking Water Through the Backwash Line

When water is leaking out of the backwash line even though the valve handle is set on the  normal “filter” mode, the problem is often the spider gasket, which can be identified by the large outer ring with spokes connecting it to a smaller inner ring. Open the multiport valve and check the gasket. If it is broken, warped or twisted, replacing it with a new one will usually fix the problem.

Pool Filter Has Zero Pressure

If you turn on your pool pump and the filter pressure gauge reads zero, the first thing to do is flick the gauge with your fingernail to see if it jumps up to normal. If this doesn’t work, look closely at the gauge to see if the dial has warped, causing it to be stuck at zero.  If it doesn’t appear to be warped and you are sure that the water flow through the filter system is normal, the next thing to check is for a clog in the air bleeder assembly where the gauge is attached. Turn the pump off and remove the pressure gauge with pliers. Run a small rod like a stick or screwdriver into the assembly to clear any clogs. If this doesn’t fix the problem, your gauge may have failed. Pressure gauges are very easy and affordable to replace.

If you have no or low pressure and you determine that the flow of water through the pump is not up to the normal rate, the issue is likely clogging before the pool filter. This could be in any number of places, including the pool skimmer basket, impeller, pump basket, or pipes. It could also be caused by an air leak in the pool pump.  

Pool Filter Has High Pressure

High pressure in your pool filter is usually caused by a dirty filter. For a DE or sand filter, keep the filter media clean by backwashing any time that the pressure gauge reads 8-10 psi higher than normal. For a cartridge filter, hose off the cartridges manually. 

If the filter pressure is extremely high, there could be broken filter parts or problems with the filter valve. Shut the pump off immediately as very high pressure can be dangerous to pool owners. Check to make sure that the return side pipes are open and call a professional if you cannot find the problem.

Pool Filter Is Leaving Pool Water Cloudy

When your pool water is constantly cloudy, first determine if your water chemistry and sanitizer levels are properly balanced. If these levels are all within the appropriate range and your water is still not clear, make sure that you are running your pool pump for enough hours each day and that your pump and filter are appropriately sized for your swimming pool. If everything checks out, try using a water clarifier or flocculant or changing the filter media.

Pool Filter Is Loud

When you hear loud noises when you turn on your filtration system, they are most likely coming from the pump motor, not the filter. The first thing to check with a loud pool pump is the water level in the pool. If the water level is normal, the problem could be caused by an air leak in the pump.

As you can see, swimming pool maintenance is easy to DIY with a few helpful tips, and that includes troubleshooting pool filter problems. Oftentimes, above ground pool and in-ground pool owners alike can fix their own minor equipment problems without having to call an expensive pool repair service. If you have problems with your pool filter or other pool equipment that we haven’t addressed here, don’t hesitate to call us today at 800-574-7665 or check us out online at doheny.com.