Pool Filter Maintenance

DEAR MIKE: I just moved into a 5-year-old resale home that has a pool. Nobody told me how to service the filter for the pool. The previous owner said that the filters are cartridges, but he wasn't very helpful in explaining what to do with them. What should I be doing and how often should it be done? -- Jerry G.

DEAR JERRY: Unfortunately, the glamour of owning a pool has drawbacks. One of them is having to clean the filters. This routine maintenance thing that should be done once per month, or sooner if the pressure on the pressure gauge is lower than normal.

The system works like this: The pump sucks water through the skimmer and the main drain. Attached to the front of the pump is a strainer basket that catches debris that gets past the skimmer's basket or that is sucked into the main drain. It also catches debris that is manually vacuumed or sucked in by the automatic pool cleaner. Debris that gets past the pump's strainer basket gets a joy ride to the filter where it is trapped.

Too much junk in the filter causes a drop in pressure, which is indicated on the housing's pressure gauge.

There are lots of different manufacturers, so pool filters come in lots of different shapes, sizes and colors. A cartridge filter such as yours looks like a large automobile air filter with pleated white folds that catch the sediment and debris.

Depending on the pool's size, you may have only one filter or you may have several. To clean the filters, you will have to gain access to them.

When you open these areas, you will hear a gurgling noise because you will be letting air into the system.

Shut off the system and open the pressure valve on top of the filter housing. Open the pump strainer, remove the basket and clean it of debris. You can use a 4d finishing nail to poke out little rocks that plug up its holes.

The filter's housing will have a removable top half. Holding the top and bottom halves together will be a stainless steel band or other mechanism. The band will have a threaded end that gets fed through a trunnion and is held together with a nut.

With the system off and the pressure gauge open and reading "zero," unscrew the nut and remove the band. The top half should lift off. Sitting on the bottom half of the housing will be a large O-ring that will get sandwiched when you reinstall the housing's lid. Inside is the filter cartridge(s).

Rock each cartridge gently to remove it and carry it out to the curb. The filter(s) will be sitting on a tray that you can lift out and clean off as well. Dismantle as many of the parts here as you can to clean them out.

To clean the filter(s), screw a sweeping attachment onto the end of a garden hose. This attachment will spray a strong stream of water out of its tip. Start at the top of the filter and work your way down, turning the filter every so often as one section becomes clean. When the water becomes clear, move to the next section.

Back at the filter housing, wipe out any sediment sticking to the walls or laying in the bottom. Re-install the tray and push the filter(s) back onto it.

Wipe any sediment from the O-ring and lubricate it. You can buy special O-ring lubricant at a pool store, or you can use Vaseline. Put a dab in your hand and go around the O-ring, but don't pull on it. You don't want to stretch it out of shape. Also, clean out the grooves on which it sits.

Place the lid back on so that you will be able to read the pressure gauge when the system is turned back on. Place the steel band back around the top and bottom halves, make sure it is seated correctly and then tighten it down. Place the pump's strainer basket back inside and replace the top.

With the pressure gauge still open, turn the system back on. You will first see the strainer basket fill with water, and within 30 seconds you should have water spitting out of the pressure valve on the lid. When water starts spraying out of the valve, close the valve.

The pressure gauge will come alive and register a reading. You will have air bubbles briefly shoot out of the sidewall jets until the air is out of the lines.

If the weather is nice and the water is warm, call me. 

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