Sand in the bottom of my pool - can't fix

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sandinmycrack
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Sand in the bottom of my pool - can't fix

Postby sandinmycrack » Tue 20 Jan, 2009 22:39

I have had a slow but steady build up of sand from my filter on the bottom of my in ground pool for several months now. It first accumulates on the steps and on the liner seams, but then is all over in a matter of days. Reading other posts/topics, I first checked to see if my pump is too strong for my filter size, causing a backwash of sand into my return pipe. Not the case, the pump GPH rating is exactly what the filter systems requires. I then took apart my filter, vacuumed out the sand and was expecting/hoping to find a broken lateral. Unfortunately all laterals were intact. Well I figured since I had the filter apart, I might as well replace all the laterals and the whole center pipe assembly, as well as replace the sand (with the correct amount of #20 pool filter sand), hoping it would fix the problem. As you can probably guess, it did not fix the problem.

I am at a loss now as to what else could be causing sand to flow into my pool. I am getting sick of spending $$ replacing my filter piece by piece to try to find a solution. Any input would be greatly appreciated!

Thanks in advance!


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Postby muss08 » Wed 21 Jan, 2009 07:51

What kind of filter (make and model)? When you replaced the center assembly did you replace orings/gaskets as well? Do you have a push/pull valve or multiport valve?
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sandinmycrack
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Postby sandinmycrack » Wed 21 Jan, 2009 17:18

My filter is a Hayward S-244T. If a multiport valve is the valve type with about 6 different settings, backwash, rinse, filter, closed, etc and rotates to each position, then that is what I have. I did not replace the gaskets because the valve was new when I moved into the house about 5 months ago, I did clean them and put fresh gasket sealer on them before re-assembly.

I just took apart the top of my filter again to inspect the gaskets (I could find 3 of them). They all look good, even the spider web looking gasket that fits under the valve handle and seperates the backwash/filter/rinse etc functions. I could see how if this gasket was messed up that it could cause the problems that I am seeing. But it looks great, is less then 6 months old, and I don't have any leaks that I can tell.
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Postby lonestar » Wed 28 Jan, 2009 10:53

When you backwash, do you also do a cycle with the filter valve on "rinse?" Is the sand appearing mainly after you backwash the filter or during normal operation?

Sand backwash:
Pump off
Put valve in "backwash" position.
Pump on. run until water runs clear (1-3 minutes.)

Pump off
Put valve in "rinse" position.
Pump on. run 1 minute or until water runs clear.

Pump off.
Put valve in "filter" position.

You can get some sand into the pool if the rinse cycle is skipped. It may not produce that much sand, but its best to check everything scince you seem to be at your wits end with this one.
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Postby sandinmycrack » Wed 28 Jan, 2009 11:13

Those are the exact steps I follow when I backwash, straight outta the manual. It is also more of a steady, all the time, build up of sand, not just after I backwash.

I'm beginning to think I have a bum multiport valve, and I'm gonna have to either replace it, or just put up with it.

I'm thinking of just rigging up a mesh bag (like the kind that fits onto my polaris), or even a thick sock over the return jets to trap the sand before it settles into my pool. Might not look all that cool but if it works, who cares. Anybody ever tried this before?
Me...

Postby Me... » Mon 23 Feb, 2009 06:23

If you brush this "sand", does it move away or disappear? Sand will move but if the material just seems to disappear then you will need to add a clarifier or flocking agent. I prefer a Polymer Clarifier, just easier and works great.

The dust comes from a chemical imbalance and if vacuumed up, just goes through the sand and back to the pool.
opa

Sand in the bottom of my pool - can't fix

Postby opa » Mon 23 Mar, 2009 10:33

i too have checked the laterals and standpipe - all look good. i replaced the spider gasket on the multiport valve. in my case there are time periods for hours or even a few days when there is no sand then there is a lot of sand - that has nothing to do with backflushing.
i'm at a loss.
thanks
steiner
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Sand in the bottom of my pool - can't fix

Postby Guest » Tue 24 Mar, 2009 01:24

Hey there steiner

Is either the pump, the filter or the filter sand new?

If the pump is too powerful for the filter, the filter too small or the sand level low, then sand is commonly seen returning to the pool.
opa

Sand in the bottom of my pool - can't fix

Postby opa » Tue 24 Mar, 2009 07:44

i have a 30" filter and a 2 hp pump. both have been in service about 6 years with no problem. i changed to Zeobrite about 18 months ago with no initial problems. i did replace the zeo with zeo when i checked the laterals last week. i used 5 bags per manufacurers recommendation.

thanks for the reply. its been two days with no sand in the pool. it is random and is sometimes a couple of tablespoons and sometimes a couple of cups.

steiner
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Sand in the bottom of my pool - can't fix

Postby Me... » Tue 24 Mar, 2009 08:38

There are good sand filters and not so good sand filters, but that will be a construction issue. No matter what a 30" filter will have a max flow of about 100gpm. The "perfect" backwash rate will be about 75gpm. Now, how do you put in a pump that will do 100gpm against all the plumbing and fittings yet only do 75gpm on backwash. Simple, you don't. Well unless a person takes the time to install and adjust valves. The pump that does a 100gpm in filter will most likely try to do 125gpm or more on backwash.

A good closed-faced impellor 2hp pump will likely try to do about 130gpm on a properly plumbed pool. A mmm ahhh errrrr lesser quality open-faced 2hp pump might be lucky to do 90gpm. In any event it appears to me that a 2hp pump is too big for that filter and will cause it to have problems or at least not perform as well as it could.

If you pump water at too high a flow through a filter on backwash you can break the laterals, blow the media out of the filter, sandblast the inside of your tank, distribute the trapped debris throughout the filter bed and more.
Guest

Sand in the bottom of my pool

Postby Guest » Tue 24 Mar, 2009 11:15

i used 5 bags per manufacurers recommendation.

its been two days with no sand in the pool.


The filter may be blowing out extra sand or the new sand is still 'settling'. If there was some overfill, the excess can work its way into the pipes during backwash and blow into the pool later.

If the amount of sand is getting less then let's wait a while and keep tabs on it.
opa

Sand in the bottom of my pool - can't fix

Postby opa » Thu 26 Mar, 2009 20:16

thanks!

i guess what has me baffled is the the fact that the discharges are random in frequency and amount?

opa
Bmguidry

Re: Sand in the bottom of my pool - can't fix

Postby Bmguidry » Sun 07 May, 2017 07:54

I recently had problems with what I thought was sand but it turns out algae. Well I have they under control but since I have changed my sand and bought pool sand from department store turns out it's 20/40 sand when I need 20 grade and had sand going through filter with the stocking test. So I purchased sand from the pool supply and it said all grades on the bag, I questioned it and they assured me it was the right sand but now my problem is worse. It's seems to have gotten better but I'm exhausted changing sand I've torn the this filter down twice and inspected everything.. please help
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Re: Sand in the bottom of my pool - can't fix

Postby Denniswiseman » Sun 07 May, 2017 09:31

20 grade silica sand is what you need 40 is smaller and can find its way through the laterals

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