Changing the sand

By Bob Dumas

Depending on the bather load, sand media can last a long time and still do a good job filtering the pool water. Lightly used pools can go as long as five years before new sand is necessary. Pools with high bather loads usually require a change every three years or so.

“I have about 25 sand filter clients, and I haven’t had to open their tanks for five years,” says Bryant Scallorn, owner of Back in the Swim in Memphis, Tenn.

But other factors must be considered. Consistently bad water chemistry or a wrong-sized circulation pump can reduce the sand’s life span and necessitate more frequent changes. When the time comes to replace the sand, use the following guidelines to make the job go smoothly:

1 Backwash the filter.

As soon as you complete this procedure, turn off the pump.

2 Remove the lid and take out all of the sand.

Techs usually have their own ways of removing the sand. It tends to involve a combination of manual scooping, along with the power of a wet vac or similar device.

“The best thing we found is something called a Muck Vac,” says Saul Rozema, owner of Sonoma Valley Pool & Spa in Sonoma, Calif.

“It is done siphon style,” Rezema explains. “You use a garden hose that creates a venturi effect and vacuums out the sand via the pressure supplied by the hose. It shoots a jet of water backward through the hose attachment, and the sand is drawn right out of the filter.”

Other techs prefer the drain-and-scoop approach. “I pull the drain plug on the filter tank and let it drain for a day or two, then use a wet vac to pull out as much of the sand as possible,” Scallorn says.

3 Look for broken parts inside the filter and replace as necessary.

It’s important to be careful when removing the sand. You don’t want to break any parts during the process. “That’s why we use a combination of scooping with a cup and then switch to a wet vac when we get closer to the laterals,” says Rick Richards, president of Arizona Quality Pool Service & Repair in Gilbert, Ariz.

“It goes faster with the cup because the vac can clog up quickly,” he adds. “But once we get most of [the sand] out, it’s easier to use the wet vac to move carefully around the laterals.”

4 Check to see that the air tube is in one piece.

It should be properly connected as well.

5 Add water to the filter to the halfway point and the proper amount of new sand.

Make sure you follow manufacturer’s guidelines.

6 Remember to clean the O-ring and threads at the top of the filter.

They should be free of sand and debris.

7 Backwash until the water runs clear.

The sand replacement now is complete. You should be ready to reset the circulation system.