Monday, March 21, 2011

How Your Sand Filter System Works

Here is what a sand filter looks like from the inside. The sand should be about 2/3 to 3/4 of the way of the filter.  ONLY USE SAND RECOMMENDED FOR SWIMMING POOL FILTERS!

The top of the filter is called the Dial Valve and changes the direction of the water flow through the filter.  You should always turn off the pump when turning the handle to a different position.

On the filter position the water will come from the pump and go down through the diffuser plate to displace the water over the sand.  Then it goes through the sand to be cleaned.  Then the cleaned water goes through the fingers, or laterals at the bottom up through the hub pipe and back to the pool.


Watch & learn about valve positions. 

Filter is the setting that you will run you filter most of the time to clean your pool.

Backwash is the setting you use to remove dirt that has collected on top of the sand in the filter. Backwashing is something you will have to do periodically.  Backwashing is cleaning out the debris that you caught in the filter.  The water goes the exact opposite way as when on the filter position.  It comes from the pump, down through the hub pipe.  One thing to note is that you should never vacuum on backwash.  All of the dirt and debris would go into the bottom of the pipe and laterals and clog them up or break them.  From the hub pipe the water goes through the laterals and up through the sand to release the debris.  The dirt and debris is then pushed out of the filter out the waste line. ne way to know if the filter is needing backwashing is to check the flow of water returning to the pool. Has it been several weeks since you last backwashed the filter or have you just vacuumed the pool? ... If a lot of dirt has collected on top of the sand in the filter,  the water returning to the pool will slow greatly. (You will also notice that you are getting little suction from your manual or automatic vacuum.) 

The best method to know when to backwash is to use the pressure gauge. (Pressure gauges often last just one pool season, as they are susceptible to corrosion. Be sure that it is working properly).  Make a note of where the pressure is after a thorough backwash of 3 – 5mins.  The pressure will be between 10 and 15 lbs depending on you distance from the pool the amount of sand in the filter and the size of your pump.  We’ll pretend that this one is 12 lbs when cleaned.  When the pressure rises 8 – 10 lbs above this level, which means when it reaches 20 to 22 lbs, that is when you backwash your filter.  You don’t have to do it every time you vacuum (if the pool isn't very dirty) or even once a week.  Letting the pressure go up actually helps your filter clean better.  But building up debris in the filter helps tighten up the sand and will catch the smaller particles in the water.  Letting the pressure rise up like this will make you water be cleaner and sparkle more. 

Also you should always backwash for a minimum of 3 minutes. This is important to get all of the debris out of the filter. Some of you might have a sight glass on the dial valve. We don't recommend watching and using this exclusively to determine how long to backwash. If you wait for it to go clear and stop you will only backwash for about a minute. That means that a lot of debris at the bottom of the filter doesn't get cleaned out. That debris is fine and it will look clear in the sight glass.  Therefore your filter will get build up much quicker and you will have to backwash more often.

If you backwash this way, by waiting for the pressure to build up 8-10 lbs and backwash for at least 3 minutes you will backwash about every 3 to 4 weeks.  And your water will never look better.

Rinse is setting you use after you backwash the sand.  After you have backwashed for at least 3 mins, you should put the filter to rinse for 30 to 60 seconds as it changes the direction of the water flow to help push all the sand back into place. Doing this "rinses" the dirty water inside the valve so it doesn't return back to the pool. Don't fret if you still get a small puff of dirt back into the pool, unless however it doesn't quit after approximately 15 - 20 seconds. For proper diagnosis, visit PoolCo. We may recommend a sand change or valve replacement depending on your situation.

Waste (or Drain) is used for draining water and (in certain necessary situations) fine and/or excessive dirt on the bottom of the pool floor.

Closed (or Test) is a great way to stop water from water flowing from the return side of the pool. Why is that cool?

When you need to remove the pump lid to empty the pump basket! (Just use a hand towel to plug the skimmer side, if you wish to stop the flow completely.)

Recirculate (or Whirlpool) used primarily for troubleshooting. The water goes only throught the valve and NOT through the sand filter. If your circulation appears to be slowing, put the dial valve to recirculate. If the circulation improves you know your filter media is the culprit. Backwash or chemically clean the sand with Strip Kwik. If circulation does not improve, then change the sand.

Winterize use this setting only when you winterize the pool. Factory installed orings inside the valve are opened to keep them from sticking together during the off-season.

2 comments:

  1. Generally Sand filter work properly long time. If we seen any problem backwash is the ultimate solution of sand filter.

    Pool sand Filter Supplier

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  2. I have an old pool sand filter and I would like to try to incorporate it into my hot tub does anybody have any comments on how I would go about doing that?

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