Getting Sand Back in your Pool?

Sand in Your Pool?

The Sandbar is open!

If you’re reading this then there may be a sand berm big enough to threaten shipping lines at the bottom of your pool. Ok, maybe that was a little dramatic, but a dusting of sand around a return line can cause a panic in any pool owner’s mind. Sadly, this is an all too common problem with sand filters but luckily there are some usual culprits that are easy fixes.

Cracked Lateral

If you ask a pool tech about a sandy pool bottom, his first question to you will be, “Did you check for a cracked lateral?” There is a good chance you did not and there are two main reasons why. First, laterals are a pain in the neck to get to, and second most homeowners don’t even know what they are.

Located at the bottom of your filter, this array of 6 – 8 perforated tubes are the last line of defense keeping sand from pouring into your pool. In a sand filter tank, water pours into the sand from the top where it filters its way down through the couple hundred pounds of sand to the bottom of your filter. This is where the little laterals come in. The now filtered water is collected by the laterals and is rushed through the center pipe and and back to the pool. The perforated holes are just big enough to allow water but prevent sand from seeping through.

If there is a crack in one of these laterals sand will find the gap and shoot happily to your pool, to ruin your day. Or at least that’s what it will feel like when you see it pouring into your pool.

The hard part is figuring out it was the laterals, the easy part is actually fixing the problem. For step by step by step instruction, review our guide How To Replace a Lateral in a Pool Sand Filter.

Did You Know?

Sand will leave a telltale streak pattern on the pool floor around the return line.  If your pool has a wide dispersal of sand then it may be getting in your pool from an outside source.

Spider Gasket

A multiport valve is like a highway interchange for your water as it routes and diverts the flow to achieve your desired setting. If water is flowing from the waste line when it is not supposed to be then the spider gasket has likely gone bad. Shaped like a wagon wheel, this gasket seals the diverter to the base of the valve preventing leaks into unselected port holes. If the water is allowed to leak into unintended ports then it may accidentally backwash debris and sand into your return.

The spider gasket wears out depending on use and water chemistry. Hard water is hard on rubber. Also, always turn your multiport’s selector handle in the same direction, whether it is clockwise or counter clockwise. If the handle is turned both ways it is more likely to warp the gasket or unseat it from its groove.

For step by step by step instructions, review our guide How To Replace a Spider Gasket on  a Multiport Valve.

Don’t Be Dense, Please Rinse.

Would you take a shower by soaping up, then lathering your hair with shampoo just to turn off the water and walk out before rinsing it off?  No, I did not think so. The same principle goes for washing out your sand filter. When a filter is backwashed, it is an absolute must that it be rinsed before returning to normal filtering mode.

During backwashing the water’s normal flow is reversed to flush out or loosen heavy dirt particles that clog the filter. Once the backwash is done those particles are deposited in the lines of the filter for the Rinse.  If the rinse step is skipped  after the backwash all that dirt and nasty stuff goes right back into your pool. Don’t be dense, please rinse.

Can’t Teach Old Sand New Tricks

If you take sand down to its singular property, it is just tiny grains of sediment and when enough is clumped together, it makes one heck of a filtering media. The bad thing is that, just like the three month old milk in the fridge, it has an expiration date. Sand can last approximately 3-5 years in a filter before it needs to be changed.  A sign of sand turning is usually high pressure  that does not subside even after a repeated backwashes. A signifier that goes along with that symptom is fine sand at the bottom of the pool.

Like water does to large rocks in a river, it smooths and wears down the size of the sand granules.  Eventually this wearing gets the sand down to a size where it small enough to fit through the perforated holes in the laterals. Next stop is the bottom of your pool. If your sand has been filtering for a few years and there is returning sand to your pool in congruence with high pressure, this may be the cause.

As usual our pool techs have a guide covering the steps to replacing your sand. If there are some steps you’re fuzzy on, check our How To Change Sand In a Sand Filter guide.

Last Call

If you have exhausted all the above options and your pool is still drowning in sand, please give us a call at 877-372-6038. Our techs love to help!

44 thoughts on “Sand in Your Pool?

  1. Would having this issue with sand going into my pool keep it cloudy? My readings are good but it’s still cloudy and it’s been running for 2 weeks. It’s an above ground and we just replaced the motor 2 days ago but still cloudy. I will have to take apart sand filter to check for crack.

  2. I have an above ground 24 ft round pool. I replaced the sand last week after vacuuming to waste and seeing debris coming out of my jet. It turns out there was less than 1 inch of sand in the filter. Less than a week later and all the sand is sitting on the bottom of my pool with debris floating and balanced chemicals. If it weren’t for my kids I would just tear the thing down at this point. Is this a gasket issue or a broken lateral?

  3. How many minutes do I need to run the filter in the “rinse” mode in order to insure I’ve rinsed thoroughly? I back-washed and rinsed the other day and it seemed to improve, but still some tell-tale signs of sand from one of the jets.
    Thank you!

  4. I just backed washed for the first time. I don’t think our pool guy ever did it for us and now that he is fired I am taking care of the pool myself. Now there is sand in my pool. I read the post sounds like I need to rinse after. My problem is that my filter is old and I don’t believe it has the rinse option. It isa push pull valve where its up for pump and down for backwash. I also can’t see where my backwash is going because the pipe goes into the ground. Any advice?

    1. The push-pull valve does not have a Rinse option, so there is nothing you can do there. But you can use a clarifier or a floc and vac chemical to clump the sand into bigger pieces the filter can catch. Hopefully, this solves your problem because it is the simplest solution.

      But as I cover in the articles sand in the pool can be a sign of cracked internal parts. Also, it can be a symptom of old sand. Old sand can begin to clump, allowing channels through which dirty water can bypass the sand and go directly back to the pool. If you can remove the cap from the sand filter you may be able to see these channels. Sand needs to be changed every 3 to 5 years for most pools. If your sand is around that age, I would plan on replacing it sometime soon so you can also inspect the internals of your tank.

  5. just had a new liner in and after filling with water I shocked the pool and noticed the next day that sand was all in the bottom of pool in clumps. could this be from the guys getting sand from the bottom underneath the liner?

  6. I could use some insight if anyone has any. I bought something at Home Depot to raise the PH Level in my in ground salt water pool and not sure if it has anything to do with it or just bad timing, but I now seem to have sand in the bottom of the pool and very little pressure on the filter. I have backwashed and rinsed but the viewing ball is completely green and doesn’t seem to be getting any clearer..

    1. To get an idea what we are working with, we would your latest water test results. Algae like high pH, so if you add too much PH increaser, you inadvertently started an algae farm. The low suction and the green sight glass sounds like your filter is clogged with algae. You have to kill the algae, and clear the dead remnants before things get better.

      The sand in the bottom of the pool could be that you filter is so clogged that it can’t pull it into the filter. Or, something like a lateral or standpipe is broken in your filter.

  7. can a bad jandy valve let sand in your pool? I had a new sand filter installed and a still get sand in the pool. I do back wash and rinse.

    1. A Jandy 2-way or 3-way diverter valve would not be the source of sand in your pool. Sand in your pool can be caused by a broken lateral, standpipe, or out of place spider gasket.

      Because your filter is new if you did not fully backwash and rinse you may have some residual sand in the lines from installation.

  8. Is sand bad for your pool pump? We are trying to fill our pool but for the past couple of days our water has had sand in it. Would it be ok to still fill it up and then let the pool clean the sand out itself?

  9. Is it normal to see fine sand in the pool for a few days after a filter change? If normal, how long does it typically take for the fines to get pushed through? The volume seems to be tapering off.

    1. There is usually some sand that finds its ways into the pool after filling your filter. But there shouldn’t be enough where there are noticeable deposits forming days after. I suggest using a clarifier so your filter can snag the fine particles, then do a thorough backwash and rinse. If the issue persists, you may have a loose or cracked lateral.

      1. We have had sand in our pool for 2 years that comes from the return jet. We have a brand new Haywood filter, backwashed repeatedly for 30+ minutes and rinsed, replaced the laterals, and are going crazy. We have had two pool guys and everybody just wants to replace what has been replaced. Any thoughts?

        1. Besides the laterals, there is also the standpipe and lateral hub that can have hairline cracks. If those have been replaced or thoroughly checked, check the multiport valve for a jiggly handle (bad diverter spring) or damaged spider gasket. Could also add some DE to the filter. Your sand could have channeling which allows the fine material to bypass sand to get sent back to the pool. DE can trap finer particles which hopefully should solve the problem.

          1. When you say jiggly handle. Do you mean up and down jiggly? Mine is secure left to right but does jiggle up and down!

          2. Up and down. The spring controls the up and down motion of the handle. If the spring is in good condition, the handle should be stiff and require effort to push it down.

  10. I put in a new Jandy STFM25 filter with Home Depot Quikrete sand in 2016 and had good operation for a year, used a little DE and Phos-free to filter more finely. And then I started seeing sand below the pool return outlets. I would just vacuumed it back into the filter since the filtering starts on top of the sand bed. This went on for a year. Have had less sand come through recently but have noticed pressure takes a long time to come up despite heavy organic and algae load in the pool. Thought I must be low on sand (have seen sand at end of discharge hose after backwashing). So I removed filter head and there seemed to be plenty, but water was nasty with lots of particulates despite backflow and rinse just before opening up the filter, and I have been backwashing often lately. Then I couldn’t get the top mount head to go down far enough to meet up with the flange on top of tank. Evidently standpipe wasn’t far enough down in tank. Decided I would have to empty sand, pull out stand pipe assembly and inspect laterals. I did and they were fine as far as I could tell. A few particles of sand were stuck in the fine passages but not enough to impede water flow significantly. There was some sand in the ends of some but not that much. I did notice some laterals were easier to remove than others, the release clip wasn’t quite as tight. Also where the two halves of standpipe body/manifold comes together it is not tight, you can even see a gap around some of the rectangular tabs where they fit into slots of the bottom piece, especially if you pull trying to separate them. All laterals appear fine and reassembled fine when I tried it outside the tank. Used a magnifying glass and found no cracks anywhere. Have not looked at spider gasket and also heard there may be some sand quality problems with Quikrete in Texas and Louisiana (I live in San Antonio). Not sure where to go from here, thinking I might get some HTH sand and compare it to what I have. Also bought a new bag of Quikrete so could compare it to the old sand. I have been going back and forth on the valve but it seems to operate fine. Always have a little sand in the glass when I rinse after backwashing. Where should I go from here?

  11. Update: I couldn’t get reasonable cost replacement sand (HTH) in my area and the quikrete sand looked uniform so I rinsed all the dirt and organic particulates out of it using a spray gun in a bucket, about a 1/5 bucket of sand at a time. Put everything back together, backwashed, resumed normal operation, and pressure started 5 psi lower than it had been before reassembly and cleaning, and it went up 10 psi in less than an hour. Backwashed again and had similar results although I got a few hours of operation before had to backwash. My pool is looking better but water is still cloudy (very unusual for my pool) so continuing to filter with a little DE added for finer filtering, just enough to boost pressure slightly. Had no sand come through sight glass (or into pool) after backwashing or vacuuming, like it would before, everytime. Not sure what was wrong with my filter or how I can prevent re-occurrence of the problem, but it seems to be functioning normally now. Cautiously optimistic that I’m on the path to clear water and low maintenance, time will tell.

  12. I’ve had sand in my pool since last season. I have replaced the lateral and stand pipe, sand and spider gasket. But still sand. I have noticed that I have to fidget with the hayward S244T multiport valve now or while in filter it sends water out the backwash port. Can the whole of the multiport valve be bad? Also I have a paramount in floor cleaning system, the control module is now clogged with sand……I think. Can it be disassembled and cleaned without opening a pandoras box of small peices? Its hard enough just getting the jets out of the bottom of the pool to clean.
    Help! PLEASE!

    1. If you haven’t fixed the issue on why the sand is in your pool, vacuum to waste. But sand is just going to find its way in the pool again.

      If you have fixed the lateral or standpipe, You can vacuum while the filter is on filter mode. The sand won’t have a way to bypass the filter.

  13. I just moved in my new home. And found out that the filter and pump were not working. Someone came to intall a new one but when I first turn it on sand comes out to the pool. Is this normal?

    1. Have you backwashed and rinsed the system since the filter was installed? During the pouring in of the sand, it can find its way into the standpipe, causing some sand issues in the beginning.

  14. I used a filter cleaner in my filter about two weeks ago. Ever since I have sand on the bottom of my pool. I can vacuum it out and it is back in three to four hours. Did the filter cleaner I used mess something up? Didnt have this problem before the cleaner

    1. The first two things I would do: check sand for channeling, and use some clarifier. Remove the valve or tank lid to check if the sand has begun to channel or open up fissures. This is common with old sand. The clarifier will clump the sand into larger clusters making it easier for the cartridge to catch it.

  15. Matthew just killing it. haha thanks for all the info man.

    So its ok to suck a ‘reasonable” amount of sand on the filter setting?

    I assume the filter basket has to be removed 1st right?
    Even if set to waste, youd still have to remove the filter basket.
    Lost a lateral last year, all fixed, but now I gotta get the sand out the pool.

    clogged the basket last year and now my pump sounds like garbage and getting no pressure..
    Dude at the pool store said sucking sand into your filter even on waste is like sandblasting the internal parts.

    he suggested a “nylon sock”?

    1. I’m not sure how much sand was in your pool from the previous bad lateral, but generally it should be safe to vacuum the sand without removing the pump basket. If you ran the pump for an extended period of time without the pump basket, there is likely debris stuck in your impeller. This would explain the sudden drop in pressure.

      Also, vacuuming the sand to waste would still mean the sand would have to pass through pump and valve to reach the waste port. I don’t think the person at the pool store was explaining the situation correctly.

  16. I’ve had sand in my pool since last season. I have replaced the lateral and stand pipe, sand and spider gasket. But still sand. I have replaced the hayward S244T multiport valve…….. still sand. Also I have a paramount in floor cleaning system, the control module is now clogged with sand……I think. Can it be disassembled and cleaned without opening a pandoras box of small peices? Its hard enough just getting the jets out of the bottom of the pool to clean. I can only think of 2 more things. 1. I cracked the new latteral on installation…..doubtful as i took my time. 2. My pump is oversized.
    Help! PLEASE!

    1. Though you say the cracked laterals or standpipe are doubtful, that is the only thing that would explain why you have a persistent sand trap in the bottom of your pool. The Hayward S244T Sand Filter can be disassembled pretty easily. Buti n-floor cleaners are a different story, there usually are a lot of moving parts.

  17. I replaced my import valve this summer. I think I have everything piped the right way. But when I vaccum the pool it throws the debre back in to the pool. I have to put a sock over the hole where the water returns to catch the debre. It’s like the dirt is not going into the filter. I have my import valve set on filter. Somebody please help me

    1. How old is your sand? Old or clumpy can cause channeling, which allows dirt to slip through the sand, and then back to your pool. Or you have broken laterals or any other of the things mentioned to check in the article.

  18. So I’m like everyone else,sand in bottom of pool . Second season and have changed sand. Yes have changed laterals and main tube, o-rings, spider gasket. Even went from 1/12 hp to 1.I never heard of putting D E in sand filter. Should I add 5 or 10 lbs.

  19. I have sand in the bottom of my pool, we have installed new laterals. Could the sand be coming from the parameter pcv lines that surround my pool and move water from filter to jets?

  20. Hello Mathew.
    I don’t have a sand probem. Yet.
    But was going to stir up the sand today and noticed the vertical pipe connecting to the valve was loose and ultimately broke off.
    So, left with the daunting task if digging out the sand and fixing it back to the hub etc.
    Question is if the valve in “bypass” mode will ACTUALLY bypass and not flush loose sand into the pool.
    Reason, is it’s HOT and needs to get some circulation before I can get to this task.
    Just thought I’d ask here.

    Thanks!

    1. I think I’m good my vari flow has a recirculate setting. So, it seems to work. Not looking forward to the job ahead tho.

    2. You are correct, the recirculate/bypass function on the multiport valve means the water never makes it into the filter tank. The setting will allow you to circulate the water without flushing 300 pounds of sand into your pool.

  21. Hi Mathew , i have been getting a little sand in my pool, its what we call a sand filter but using the glass media, backwashed and filtered to watste still comes back?

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