How to Vacuum a Pool with a Cartridge Filter

Key Difference from Sand Filters

Sand filters have a multiport valve with a WASTE setting that routes water directly out of the pool without passing through the filter. This is useful when vacuuming heavy debris or after algae treatment - the debris goes straight to waste and does not go through the filter media.

Cartridge filters do not have a multiport valve. There is no WASTE setting. All water that enters a cartridge filter passes through the cartridge before returning to the pool. This means:

• All vacuumed debris goes through the cartridge
• Heavy debris loads the cartridge faster than routine filtration
• After a dirty vacuum session, the cartridge usually needs cleaning

This is not a problem for routine pool maintenance. It only becomes relevant when vacuuming very heavy debris or after an algae bloom.

Equipment You Need

• Pool vacuum head
• Telescoping pole
• Vacuum hose (long enough to reach all areas of your pool)
• Skim-vac plate or skimmer adapter (connects vacuum hose to skimmer basket)
• Garden hose (to prime the vacuum hose)

How to Vacuum a Pool with a Cartridge Filter

Step 1: Check your filter pressure baseline

Note the pressure gauge reading before you start. Write it down or remember it. A clean cartridge should read somewhere between 8-15 PSI depending on your system - this is your baseline. You will want to stop vacuuming and clean the cartridge if pressure rises 8-10 PSI above this starting point.

Step 2: Brush the pool walls and floor first

Brush debris off the walls and into the water 30 minutes before vacuuming. This lets debris settle to the floor where the vacuum can reach it more effectively. Brushing also loosens biofilm and fine debris that the vacuum needs to pick up.

Step 3: Assemble the vacuum

Attach the vacuum head to the telescoping pole. Connect one end of the vacuum hose to the vacuum head fitting. Make sure all connections are snug.

Step 4: Prime the vacuum hose

Before connecting to the skimmer, you need to fill the vacuum hose with water to remove air. Air in the hose will break suction and make the vacuum ineffective.

To prime: hold the open end of the vacuum hose over a return jet with the pump running. Water from the jet will fill the hose from the bottom up. When water flows continuously from the end you are holding, the hose is primed.

Alternatively: submerge the entire hose in the pool until all bubbles stop coming out.

Step 5: Connect to the skimmer

With the hose still full of water, place the vacuum head in the pool. Keep your hand over the open end of the hose to prevent air entering. Walk to the skimmer, remove the skimmer basket, and place the skim-vac plate over the skimmer opening. Connect the vacuum hose to the skim-vac plate.

If you do not have a skim-vac plate, plug the hose directly into the skimmer suction port at the bottom of the skimmer basket housing. Some skimmers have a dedicated vacuum port separate from the basket.

Step 6: Vacuum slowly

Move the vacuum head slowly across the pool floor in overlapping passes, similar to mowing a lawn. Work from the shallow end toward the deep end.

Slow, deliberate passes pick up more debris than fast sweeping. Moving too fast kicks debris up into the water column where it takes time to resettle.

Step 7: Monitor filter pressure

Check the pressure gauge every 5-10 minutes. When it reads 8-10 PSI above your starting baseline, the cartridge has loaded enough debris to restrict flow. At this point:

1. Turn off the pump
2. Remove the vacuum hose from the skimmer
3. Remove and rinse the cartridge
4. Reinstall the cartridge
5. Restart the pump and resume vacuuming

For a routine clean pool, you may vacuum the entire pool without the pressure rising enough to require a mid-session cartridge clean. For a pool that has not been vacuumed in several weeks, expect to clean the cartridge at least once during the session.

Step 8: Clean the cartridge after you finish

After vacuuming, check the pressure again. If it has risen from your baseline, clean the cartridge before the next filtration cycle. Leaving a loaded cartridge running at elevated pressure stresses the pump motor.

Vacuuming After an Algae Bloom

Algae loads a cartridge filter far faster than normal debris. Algae particles are microscopic and coat the cartridge material quickly.

The correct approach for post-algae vacuuming:

1. Shock the pool and wait 24-48 hours for algae to die and settle to the floor
2. Test and adjust chemistry so chlorine is back to normal levels
3. Vacuum the dead algae off the floor using the cartridge filter - plan to clean the cartridge 1-3 times during the session
4. After vacuuming, clean the cartridge thoroughly with a chemical filter cleaner to remove the fine algae particles that hosing alone does not clear

See our guide on how to clean a pool cartridge filter for the full cleaning procedure including the chemical soak method for heavy contamination.

Maintaining Suction During Vacuuming

If suction drops while vacuuming, the most common causes are:

• Air in the hose: The hose floated up and air entered. Re-prime by holding the hose end over a return jet again.
• Skimmer basket full: The skimmer basket filled with debris and is restricting flow. Empty it.
• Cartridge pressure too high: The cartridge is loaded. Stop and clean it.
• Pump strainer basket full: Less common, but check the pump basket if the above three do not solve it.

After Vacuuming: Next Steps

After a routine vacuum, check that the pressure gauge has returned to near baseline after your cartridge clean. Run the filter for a full filtration cycle (typically 8-12 hours) to clear any remaining fine particles stirred up by vacuuming.

For the full cartridge filter maintenance schedule including how often to clean based on pressure, see how often to clean a pool cartridge filter.