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Thread: Sand Filter Pressure

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    Sand Filter Pressure

    Hello all, my Mom has a IG pool with a sand filter (triton T100 I believe it is ). Last week her Hayward cleaner stopped moving as well as it use to, so she took it in and they replace the flappers but stated to her that it showed signs of being used with too much suction (not sure if related). She reinstalled the cleaner with no improvement, notice her pressure was high on her filter so she back washed. The pressure did not drop at all but instead remained at about 22psi. I stopped by last night and she told me of the problem so I tried back washing as again the pressure did not come down at all. It appears to me that the filter has a clog at some point. Where is the best place to start looking?

    I read somewhere that there is a chemical cleaning process that can be completed prior to ripping it apart and changing the sand.

    Filter appears to be 10+ years old, she has owned the house for 5 and it has never been cleaned to her knowledge. .

    I know zip about sand filters so .. Next steps ?

    Thanks.
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    Mod Squad JohnT's Avatar
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    Re: Sand Filter Pressure

    Does the gauge go to zero when the pump is off?

    How long did you backwash? 3-4 minutes backwashing followed by 1 minute rinse should clear a dirty filter.
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    Re: Sand Filter Pressure

    I was in the same boat - bought my house 2 years ago, TR-100 over 10 years old with no idea of maintenance schedule - and I replaced my sand in May. It really wasn't very hard at all (if you're up to some heavy lifting), and at least now I know what I'm starting with. I just unscrewed the top and upper intake, used a shop-vac to extract the old sand (it was mostly dry from winter storage), unscrewed and inspected the laterals and hub, screwed it all back together with teflon tape, filled it half-way with water, and added new sand. It took just under 11 full bags (550 lbs). There's not much to the filter at all; you can find cut-aways online so you know what you're dealing with. Just don't be afraid to get dirty, be gentle with the internal fittings, and take your time.
    44,000 gal gunite IG, Pac Fab TR-100 (30") Sand Filter, Polaris 3900

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    Re: Sand Filter Pressure

    You know... I did not check the gauge with the pump off.. I'll do that.
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    Re: Sand Filter Pressure

    Called and had her go out and look. Gauge reads Zero with pump off.


    Is a Chemical cleaning just a gimmick or a valid process? I've never heard of it but I have a DE filter.



    I think I'll pass on the chemical process and just replace the sand so we know it's fresh. How big of a deal is that process? Is there a difference in brands of sand ?
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    Re: Sand Filter Pressure

    Quote Originally Posted by Phillbo
    How big of a deal is that process? Is there a difference in brands of sand ?
    The hardest part is obviously getting the old sand out. The wet/dry vac and mostly dry sand made it fairly easy for me. Of course, you can use a can or scoop instead, but there is A LOT of sand in a TR-100 and the opening is pretty small. Once it gets low enough, you can open the drain valve and wash the rest out with a hose (if you want to make a mess). If you're putting your arm inside, wear long sleeves to avoid the fiberglass.

    Once it's empty, inspect all the parts inside for damage. Everything simply unscrews, just be gentle. Any POOL FILTER sand (from a pool supply store) should do so long as the grain size is correct as specified in the manual. You'll need 550 to 600 lbs. Fill the filter about half way with water before adding new sand to protect the laterals and only fill it with sand to the height specified in the manual (about 12.5" from the top). Being my first time, the whole process took me maybe 3 or 4 hours. You should be able to find detailed step-by-step instructions on the process and the instruction manual for the filter with a quick google search.
    44,000 gal gunite IG, Pac Fab TR-100 (30") Sand Filter, Polaris 3900

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    Re: Sand Filter Pressure

    Thanks for the input . Is the Drain Valve the same as the Back Wash valve or is their a valve on the bottom of the tank? I'm sure it will become obvious once I tear into it but to this point I have not investigated much yet..
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    Re: Sand Filter Pressure

    Philbo,

    I would go slow on changing the sand. It is not clear to me that is what needs to be done. A filter psi of 22 does not indicate a major problem, necessarily.

    Are you getting good flow from the returns into the pool.

    There are many people on this forum who go years and years without changing sand. If it were my pool, I would investigate the problem a little further.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Re: Sand Filter Pressure

    The psi of 22 is not the problem but there is a problem somewhere given the last 4 years it ran at 10 psi after being back washed and last week the cleaner stopped working and the filter pressure stopped dropping after a back wash..

    The flow to the returns appears to be normal. For all we know, the sand could be original from 1985 when the pool was installed ..

    where else should I look?
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    Re: Sand Filter Pressure

    If the return flow appears normal, I would suspect the guage.

    The pressure goes up in a pool circulatory system when something is obstructing the flow of water from the pump to the pool. If your sand was 'clogged" it could cause that obstruction easily enough but the flow back into your pool would be noticeably reduced.

    If the water is flowing back into the pool without apparent obstruction, it is most likely a faulty guage.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Re: Sand Filter Pressure

    OK, I'll check the gauge but how could a faulty gauge cause the cleaner to barely move? They both symptoms started at the same time.

    Remember now, this is not my pool, i have not a lot of baseline when it comes to typical flow etc... but the flow back into the pool seamed pretty strong to me.
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    Re: Sand Filter Pressure

    but the flow back into the pool seamed pretty strong to me.
    Yeah, that's an unknown. I realize you didn't have good info before the issue.

    Just how it relates to the cleaner, I'm not sure. Those suction side cleaners seem to only want to operate effectively within a pretty narrow range of water flow so it may be related.

    I had a suction side cleaner that became so persnickety about flow that I finally got rid of it. I'm not saying that's the issue but I am saying the mechanism within that cleaner could be contributing and I have no idea how to address that.

    If you suspect the sand is the "blockage", simply remove the top lid of the filter and inspect it.
    Dave S. - Forum owner
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    Re: Sand Filter Pressure

    What cleaner is this? Navigator/Pool Vac? Did you try replacing the pods yet? That's what usually makes them work.

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    Re: Sand Filter Pressure

    Also the sand usually is 20/30 grade Silica sand. Same sand they use in sand blasting.

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    Re: Sand Filter Pressure

    It's the Navigator. 2 years old.


    I'm going to swap out mine for hers and see if it works ok... just to rule out a cleaner issue.
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    Re: Sand Filter Pressure

    If you have a multiport valve with recirculate you could try it in that position, I think that bypasses the sand.If the pressure does not go down then I would look for a blockage or maybe a bad guage.

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