Filter is shooting sand back into the water when on filter mode. I just replaced the sand, and last year replaced the 5 spoke gasket. I checked the gasket this year and it still looks good. I've had the same pump and filter for 8 years and this is the first time its done this. I am also getting alot of particles back into the pool when vacuuming. You can actually see the dirty water go back into the pool. I did buy the sand last year and it sat outside all winter, is the sand bad?

The Hayward Pro Series Sand Filter uses an O-Ring on the stand pipe to separate water returning to the pool, after being filtered, from water coming into the filter from the pool. If this O-Ring is broken, missing or sufficiently worn, small particles of dirt and sand can by-pass the sand filter and return to the pool without being properly filtered by the sand filter.

This can be especially evident just after backwash and rinsing of the sand filter bed. During this time water flows up through the sand bed, opposite the direction in normal operation. This forces the top-most material of the sand bed to dislodge and wash out of the filter to waste. It can also force fine particles to enter through a faulty O-Ring into the pool return stand pipe. Then, when returning the filter system to normal operating mode, those fine particles enter the pool through the water return piping and collect on the bottom of the pool -- mostly small sand particles but potentially filtered debris particles that were captured on top of the sand bed.

To avoid this problem it's wise to replace this O-Ring every few years. And make sure to follow the manufacturer's recommendations regarding the amount of sand to fill when replacing sand. It's important to keep the top of the sand bed at the correct level to insure proper filtering and minimize stray particles coming back into the return water.

The back pressure at which it's time to backwash a sand filter is about 6-8 psi above the baseline pressure of a clean filter. Just after following the procedure to backwash and rinse your filter, check the sand filter's back pressure at the time you return the pump and filter system back into filter mode. This is the baseline pressure of your clean filter. As the filter gathers particulates from the pool water, the back pressure will rise over time, as indicated on your pressure gauge. Once the pressure reaches 6-8 psi above the baseline, it's time to backwash.

Some advice: Don't assume the baseline pressure will remain the same for your sand filter. The baseline pressure will change over time and when the sand media is replaced. Typicallly baseline pressure will go up slightly over a season due to captured particles that are difficult to backwash out. Use of a filter cleaner will help remove these captured particles.

More advice: Even with the use of filter cleaners and proper backwashing, sand media will not last forever. The constant water flow and movement of particles in the sand over time shears the surface of each little sand grain. Like a river flowing over rocks, over time each sand grain surface is smoothed, and thus its effectiveness for capturing small particles is reduced with ongoing use. A typical rule of thumb is to replace the sand media +/- 5 years. Some pool owners do it more often, some less. It depends on how long your pool season is each year and how much debris the filter much extract from the pool water.

sand filters only have limited filtration. If the dirt is very fine such as dead algae, it will go right through the filter. Use a clarifier to help give the filter finer filtration. Do not vacuum until you can see what you are doing, then vacuum on 'waste'

Your sand filter has developed a fault.
Normally water is filtered from the top of the sand filter through the sand to the bottom of the sand filter into the spoke pipes. The filtered water is collected by a pattern of spoke pipes that is connected to the collection box. These pipes only allow water to pass through to the return riser pipe to return the water to the pool via the selector valve.

This problem happened to me too, the fault was at the bottom of the sand filter, at the connection box, it had collapsed/cracked and allowed the sand entered the riser pipe to the selector valve that controls the backwashing, rinse, and filtering etc. and the sand and water is returned to the pool via this valve.

The can be repaired, it requires removing the control valve, removing the sand to get access to the riser pipe, and the collection box and spoke pipes. the the damaged collection box can be repaired.
Put back together in reverse order.

Are you sending thw water to waste or ar you filtering it? If you are filtering it through a multi port valve, the spider gasket could be faulty. Proper way to vacuum is through the filter then back wash the filter after cleaning the pool.

I suggest you take the top from your filter and inspect the sand, it should be solid over the top. Have you tracked the pressures over the past year? When was the last back wash? You should back wash only when the pressure goes up 20 PSIG from start (when the filter is clean and free of debris.)

Tell me more please. . . .

There is more than one version of these valves. The model like sp072 has a 5 spoke spider gasket that has one opening larger than the rest. Be sure it is in position so that the large opening lines up with the large opening in the valve. If it's a SP0714 then the rubber is molded on the valve itself and would have to be replaced together. In either case, the seal is provided by the spring pressure forcing the valve faces together. That is why you should depress the handle, and only turn the valve while it's depressed, and the pump is off. After you turn to the selected location, then you release handle, and the valve surfaces should spring back together. Be sure the lever has spring tension on it in case you left it out while working on it) You can download complete manuals from www.haywardnet.com Good luck!

if you are on city treated water, sand will last aprox. 7 years, if on well water typically 3 - 5 years. so yes, could be a sand issue. also, double check that the there is no water trickling out the backwash / drain outlet of the filter, this could indicate that the diverter valve gasket (spider gasket) could be worn and cause sand from the filter to flow to the pool. this is a common problem if you move the position selector often with the pump still running - the pump should always be off when moving the handle. good luck!

This is usually a problem with the valve, not the filter. You will need to take the valve apart, look for an O-Ring that has gone bad, usually on the handle (top section) part of the valve. The O-RIng may look like a wagon wheel that is missing a spoke.

Your valve gasket is likely damaged allowing water to bypass the sand bed. Opening the valve you will likely see a damaged "wagon wheel with spokes looking" gasket. Try replacing it if it is at all creased or cut up.

could possbly be a bad gasket on the vari-flow valve. When is the last time you backwashed?