5 Common Swimming Pool Sand Filter Problems

Sand filters in swimming pools play an important role in keeping the water fresh and clean. As the pool water is pumped through the filter, the sand inside the tank traps dirt and debris. Without this feature, your pool will quickly turn dirty. If you have sand filter problems, the quicker you can resolve them, the better. This article will detail 5 common sand filter problems and how to fix them so you can restore your pool to its radiance!

Safety tip: Before beginning to investigate or fix the problem, be sure to power off the sand filter and set the mode to "winter".

A multi-port valve on a sand filter is a powerful pool piece of equipment. As the name suggests, multi-port valves have many internal ports or channels for the flow of pool water. These valves have a lever handle that you can turn to set one of seven filtering functions. By changing the position of the handle, you can activate the filter, backwash, recirculation, waste, rinse, winter, or off settings. Depending on the settings you choose, the pool water will be delivered in a certain way. This feature allows your pool filter to perform several maintenance operations efficiently.

Still, if your multi-port valve handle is loose or damaged, you won't be able to use all the functions the valve has to offer. Below we explain how to fix a malfunctioning handle.

If you notice your multiport valve handle wobbling, it may be due to a loose or damaged spring within the key seal assembly. Thankfully, replacing the spring is fairly straightforward.

1. Unscrew the valve cap to access the keycap assembly.

2. While pushing down on the top of the assembly, use a hammer and screwdriver to lightly tap the pin holding the handle in place until it pops out. Unless you can grow an extra set of arms, you may need a backup for this step!

3. Set the handle aside and lift the top of the assembly. Check the integrity of the gasket located under the handle - replace if worn.

4. Remove the current spring and replace it with a new one.

5. Also check the O-ring on the stem. Clean or replace if dirty or damaged.

6. Carefully reassemble the key seal, making sure all parts are back in the correct position.

7. Tighten the cover.

A damaged multi-port valve handle may seem like a bigger problem than a loose one, but it's actually easier to fix. Follow steps 1 and 2 listed above to remove the valve handle. Check the gasket again and replace it if needed. Attach the new valve handle by inserting the pin back into place, then screw the cap back on.

After backwashing the filter, it is normal for a little water to drip from the waste pipe of the sand filter. However, if the drip persists for a long time and/or the drip becomes more intense, you may experience problems with your hands. Oftentimes, old or damaged star washers are the culprit behind leaking waste lines.

1. Unscrew the valve cap to access the key seal assembly.

2. The star washer is either glued to the rotor - the bottom of the entire key seal assembly - or inside the valve body.

3. If the star spacer sticks to the rotor, the entire rotor needs to be replaced.

4. If the star washer is in the valve body, peel it off by hand or pliers.

5. After removing the old star washer, clean and dry the valve.

6. When everything is dry, apply a small amount of glue to the edge of the valve groove and place the star washer flat side down in place.

7. Let the glue dry completely, then put the key seal assembly back into place.

After changing the sand in the filter or running a backwash cycle, it is common to see a small buildup of sand on the bottom of the pool. However, if the amount of sand in the pool increases, you may be dealing with side or riser damage inside the filter.

On the sides are the plastic parts at the bottom of the sand filter with small slits to keep the sand out. It could also be a broken riser or diffuser - if it breaks, all the internals will leak sand into the pool.

Solution? Drain the tank, scoop out the sand, and replace the entire set of manifolds. If the filter sand is still in good condition, you can reuse it. Generally speaking, pool filter sand will last about 5-7 years before it wears out and needs to be replaced.

While broken side pipes or risers are often the cause of sand leaks, here are some other potential issues that could turn your pool into a beach:

Worn sand: Over time, the sand becomes smooth and unable to trap dirt and debris.

Calcified sand: Very hard water minerals will turn sand into sandstone.

"Mudball": Oil collects in the sand tank, forming a gooey ball in the top third of the sand.

Bypass: If the pump is too powerful, dirt may be bypassed directly through the filter without proper treatment.

For most pools, the ideal sand filter pressure range is 10 to 25psi. Blockages or incorrect sand levels in the system are often the cause of pressure increases or decreases. If the sand filter pressure drops below 10psi, first check for blockages in front of the filter. Clean your pool skimmer and check the impeller in the pump. If your pump is fine, the problem may be due to a low pool level or insufficient sand in the filter. Top up the pool or add more sand to the filter.

If your sand filter pressure is too high, the first step is to backflush the filter. Dirty sand can cause filter pressure to rise. If that doesn't fix the problem, there may be too much sand or clogging in the filter. Check your sand levels and remove excess sand if needed. If you suspect an obstruction and are unsure how to clear it, contact a professional for help.

Sand filters are high-pressure equipment. So if the tank breaks, it needs to be replaced. Replacing an entire sand filter is usually cheaper than repairing a cracked tank.

It is important to diagnose and repair sand filter problems quickly. A well-functioning sand filter is essential to keeping your swimming pool clean and enjoyable. Thankfully, many common sand filter problems are relatively easy to fix. If you want to buy a new swimming pool sand filter, please contact us.

MAYGO is a professional custom pool filter manufacturer. MAYGO POOL focuses on providing professional technical solutions for residential and commercial swimming pools. At present, we have provided swimming pool solutions to thousands of customers in North America, South America, Europe, Australia, etc. We have a team of engineers and mold-making with extensive experience in electromechanical and CFD hydraulic design. They are fully committed to research and development. MAYGO has obtained a number of patents, as well as CE, SAA, ETL, CCC, CANS certification.