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Thread: Is this 40 yr old sand filter working?

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    Is this 40 yr old sand filter working?

    I have been reading this forum for two years and found it very valuable. For my own pool, water looks good and I am happy with my water clarity, but I suspect my old 1975 Hayward 22-inch sand filter is not working well. I want to avoid the trouble and inconveniences with a broken filter. I am asking for your guidance to make sure my filter does its job.

    Here are some observations/symptoms:

    1) When first open the pool (or clear a green pool due to negligence) and maintain shock level, I see no improvement on water clarity with the filter running continuously for a few days. Water is always milky blue color (full of dead algae, I think). To clear the pool, I do a one-time floc and vacuum to waste. After that, the water remains clear under routine pool care.

    2) Filter pressure as shown by the gauge never increases (always 15 psi in filter mode), even after filtering the milky blue water for a few days. I thought the pressure should gradually increase as the filter catches more particles from the pool (and a backwash is recommended when the pressure increase by about 20%). The filter pressures with different multi-port-valve positions are
    filter - 15 psi
    recirculate - 15 psi
    backwash - 10 psi
    rinse - 10 psi
    waste - 6 psi

    3) Vacuuming through the filter in general makes the water cloudy.

    4) I have a little sand on pool bottom. I am not very sure but perhaps a little sand could appear at the pool bottom after backwashing-rinse and turning back to filtering. I also have less sand (maybe only 60% of the sand) than the spec of the filter manual. I tried adding sand but it caused more sand at the pool bottom. So I reduced the sand level to 60%.

    5) The backwash hose looks long (about 20 ft I think). Not sure if it is too long and prevents a good back wash.

    6) I don't have a bottom drain but I think circulation is good. All circulation operations looks normal.

    What concern me in practice are 1), 2), and 3). Overall, I suspect my sand filter is not working well. I disassembled the filter and this is what I found:

    a) The spider gasket and the multi-port handle are new. I think they work well. They used to leak and I replaced them two years ago.
    b) The plastic valve itself is old. I see no obvious leaks. But I am not sure where to look at exactly.
    c) The stand pipe shows no obvious problems either.
    d) The sand looks fine, loose and clean. I don't think "deep cleaning" is needed. But there is less sand than it should be because of the "sand in pool" issue. I guess having less sand is not detrimental. A shallow top layer of the sand does most of the work?
    e) There are no laterals as commonly used in today's sand filters. My filter has a metal screen under the sand as the underdrain. I think it is much sturdier than plastic laterals. I don't think there is any way for the underdrain to go wrong.

    How can I test a sand filter to make sure it works well? Should I take any steps to replace the filter valve, or buying a new filter is just simpler? but I feel not very comfortable doing any change without a good diagnosis.

    Thank you!
    22,000 gals in-ground pool, 16 x 32 ft rectangle, Vinyl liner
    Hayward sand filter (model 225, tank diameter 22'', 50 gpm, yr 1975), Marathon 3/4 HP pump (model 1081, 3450 rpm)

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    Re: Is this 40 yr old sand filter working?

    What is the screen at the bottom made of? Have you taken the sand out and looked at the screen to make sure it is still good as in not rusted or such? It might be clogged. When I took my sand out I was VERY surprised to see how many of my laterals had sand stuck in them.

    Gauge-does it drop down to 0 when you turn the pump off? I would look into getting a new one or at least taking it out and cleaning it if it is one of the good one. There might be something clogging it.

    When I take my sand out I use a shop vac. I put the vac in my wheel barrow so I do not have to bend down so much. Once the vac gets full I just dump it out into the WB and keep going. It also helps really clean the sand. With you using floc you might have all kinds of stuff in there.

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

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    Re: Is this 40 yr old sand filter working?

    I did take the sand out to expose the metal screen. It looks like stainless steel, shiny, with no rust at all. It is also mechanically very strong. I actually like this design more than the plastic laterals.

    If the filter is clogged, I would expect the pressure in "filter" mode be higher than "recirculate" mode? but currently they show the same 15 psi. Is this strange enough?

    The gauge does drop down to 0. Some times I have the skimmer basket clogged and reduced circulation, then the gauge shows reduced pressure. This is why I think the gauge is working.
    22,000 gals in-ground pool, 16 x 32 ft rectangle, Vinyl liner
    Hayward sand filter (model 225, tank diameter 22'', 50 gpm, yr 1975), Marathon 3/4 HP pump (model 1081, 3450 rpm)

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    Piolin's Avatar
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    Re: Is this 40 yr old sand filter working?

    Did you look at this link...

    Deep Cleaning a Sand Filter

    Starting day 5/25/2015 INTEX AGP 24'x12'x54" 8,400 gal, with salt and borax, INTEX 3,000 GPH pump with 16"sand filter, WM Hayward Skimmer, Intex SWG CG-28669, 1 1/2" hard plumbed PVC, Lil' Shark Vacuum With Leaf Canister, TF100 test kit, speed stir, K-1766 Taylor salt test

    mod note: fixed sand filter link
    8,400 gal Intex, 3K GPH pump, 16" sand filter, SWG CG-28669, TF100 test kit, speed stir, K-1766 Taylor salt test.

    The corner stone of TFP
    Pool School - Chlorine / CYA Chart

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    Piolin's Avatar
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    Re: Is this 40 yr old sand filter working?

    Thank you... 😊

    Starting day 5/25/2015 INTEX AGP 24'x12'x54" 8,400 gal, with salt and borax, INTEX 3,000 GPH pump with 16"sand filter, WM Hayward Skimmer, Intex SWG CG-28669, 1 1/2" hard plumbed PVC, Lil' Shark Vacuum With Leaf Canister, TF100 test kit, speed stir, K-1766 Taylor salt test
    8,400 gal Intex, 3K GPH pump, 16" sand filter, SWG CG-28669, TF100 test kit, speed stir, K-1766 Taylor salt test.

    The corner stone of TFP
    Pool School - Chlorine / CYA Chart

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    Re: Is this 40 yr old sand filter working?

    Yes I have looked at this link to Deep Cleaning a Sand Filter. My understanding is the "deep cleaning" dislodges the debris from the bottom of the sand bed. But my sand all looks like new when I checked

    It would be very useful if there is a practical and effective way to check if a filter is functioning well. I head I can pore some DE to the skimmer and see if it comes out of the returns. But I am not sure if this really works because we know a sand filter can only filter a fraction of small particles. So even if DE comes out of the returns, the filter can still be working well. The water needs go through the filter probably many times to effectively clean all DE. Also, if DE goes into my pool, I am afraid I have no easy way to get them out any more ...

    How can I confirm my filter is working or not working?

    Forest.
    22,000 gals in-ground pool, 16 x 32 ft rectangle, Vinyl liner
    Hayward sand filter (model 225, tank diameter 22'', 50 gpm, yr 1975), Marathon 3/4 HP pump (model 1081, 3450 rpm)

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    Piolin's Avatar
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    Re: Is this 40 yr old sand filter working?

    I usually slowly add 1/4 cup of DE through the skimmer to improve filtration and I always look at my return, and never saw any cloud of DE coming out, but I know every pool is different ...
    8,400 gal Intex, 3K GPH pump, 16" sand filter, SWG CG-28669, TF100 test kit, speed stir, K-1766 Taylor salt test.

    The corner stone of TFP
    Pool School - Chlorine / CYA Chart

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    Re: Is this 40 yr old sand filter working?

    Forest, A few questions come to mind:
    1) When you bleed the filter's air valve what PSI does it drop to and rise back up to? Is it quickly?
    2) How old is your pump and have you inspected its impeller for wear/damage?
    3) How many suction lines/skimmers do you have? Does isolating them make a difference in the filters performance?
    4) Have you measured the flow(gpm) to & from the filter?
    5) Is your flow rate ok for your filter?

    My neighbor's son works for Hayward's Commercial Pool Products in Rockville, MD. He was here visiting on Sat ... not sure if he's still around ... but if you post the exact Model # & S/N of the filter - I'll ask him about it for you. Maybe he give you some advice or forward the maintenance manual and the sand replacement specs / procedures to you.
    Last edited by CNJ_EC; 07-04-2016 at 12:46 AM. Reason: update
    60' x 30' IG concrete pool built in 1998. 2 - 2" Suction Line( 2-Skimmers/2-Way Jandy Valve per line); 1 - 3" Suction Line (Floor Drain/ 2-Way Jandy Valve); 1 - 3" Return 8 Floor Outlets; 1 - Pentair IntelliFlo VS Prog Pump 240V/3HP (2013); 2 - Triton TR-140C Sand Filters Tandem Config (2013); 1 - In-line Chlorinator (2015). Misc - Pool Use: May to Sept; Turnovers: 2.5; Pump Operation: 23hrs

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    Re: Is this 40 yr old sand filter working?

    I guess having less sand is not detrimental.
    Why would you think that? If less sand was needed, filters would be smaller. Larger filters are used in larger pools because larger pools require more filtration. I think your first issue is to bring the sand up to the proper level and then try to figure why you are losing sand.....if you are.
    I am not very sure but perhaps a little sand could appear at the pool bottom after backwashing-rinse and turning back to filtering.
    You need to confirm that that is filter sand. It should be gritty and easily captured and rolled between your thumb and forfinger. If brushed it should fall quickly back to the pool floor.

    Redbluepool,

    I am not going to hijack this thread but move your post first to "agree to disagree" and then we can discuss sand.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Is this 40 yr old sand filter working?

    Thank you Piolin. Your experience is very helpful. I am interested in trying adding DE through the skimmer and see if any cloud of DE comes out of the return.
    22,000 gals in-ground pool, 16 x 32 ft rectangle, Vinyl liner
    Hayward sand filter (model 225, tank diameter 22'', 50 gpm, yr 1975), Marathon 3/4 HP pump (model 1081, 3450 rpm)

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    Re: Is this 40 yr old sand filter working?

    Hello CNJ_EC
    1) I am ignorant about bleeding the filter's "air valve". Not sure if I have one... Sounds interesting. Could you educate how this is done? The pressure gauge changes almost instantly when I switch between different multi-port valve positions, but this is probably not what you are asking.
    2) The pump looks to be several years old. It's Marathon model 1081. I did not inspect its impeller. The return jet is strong -- I can hardly screw the eye ball back in with the pump running. I also lose water quickly when backwash or vacuum to waste. So I have assumed the pump and impeller is okay.
    3) The pool has only a single suction line, connected to a skimmer and also a suction inlet about 1 ft below the skimmer. I always open the underwater suction inlet for better circulation. btw, the pool has no drains at the bottom. It has two returns.
    4) I did not measure the flow (gpm) to & from the filter. I can probably measure in rinse mode with a bucket. Will try.
    5) I cannot answer 4 so not sure if flow rate is okay. The filter rate given by the filter manual is 50 gpm for 3/4 HP filter (12 hr turn over is 36,000 gal, my pool capacity is 22,000 gal). The pump seems to be pumping water well. ~50 gpm seems reasonable.

    The filter model is Hayward 225. The previous owner actually gave me the manual which include sand capacity and procedures.
    Please ask your Hayward friend for advice if you have a good chance. Much appreciated! CCI07052016.jpg
    22,000 gals in-ground pool, 16 x 32 ft rectangle, Vinyl liner
    Hayward sand filter (model 225, tank diameter 22'', 50 gpm, yr 1975), Marathon 3/4 HP pump (model 1081, 3450 rpm)

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    Re: Is this 40 yr old sand filter working?

    Hello duraleigh,

    My statement about sand was bold. I agree a sufficient filter area and a proper sand level is important for the best filtration performance.

    For the purpose of diagnosis of my filter, my assumption was that a filter with less sand should still "operate". I mean it should still filter water, but take longer time. I read somewhere that only a shallow top layer of the sand bed does most of the filtration. So with 60% of sand, I hope the filtration performance can be >60% but of course <100%. Maybe this is not a good assumption and I am overly optimistic?

    Regarding whether the sand is filter sand: I have an eyeball by my pool stairs and I can clearly see some sand settles on the stairs. It looks the same as the sand I put in the filter. Yes it settles to the pool quickly.

    Maybe I should focus on the sand on the floor issue. If it is really filter sand, does it mean the filter is very likely to have leak somewhere?

    Thank you!
    22,000 gals in-ground pool, 16 x 32 ft rectangle, Vinyl liner
    Hayward sand filter (model 225, tank diameter 22'', 50 gpm, yr 1975), Marathon 3/4 HP pump (model 1081, 3450 rpm)

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    Re: Is this 40 yr old sand filter working?

    The pressure gauge changes almost instantly when I switch between different multi-port valve positions,
    That's a no-no. Always move the valve when the pump is off and always move it in the same direction each time.
    Maybe I should focus on the sand on the floor issue. If it is really filter sand, does it mean the filter is very likely to have leak somewhere?
    I agree that should be your focus but make sure it is dumping enough to be significant. A teaspoonful of sand is nothing in the big picture and SOME sand will leak in a perfectly working filter.

    I don't see the "screen" you are talking about in the diagram.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Is this 40 yr old sand filter working?

    Forest,

    That filter isn't a Hayward product. I was manufactured by a company called Gold Marc(no longer in business) it was either purchased with a Hayward Multi-port Valve or the Hayward Valve was added at a later date. I just sent you message - please read it and then I'll post the remaining info here in the thread.

    TJ
    60' x 30' IG concrete pool built in 1998. 2 - 2" Suction Line( 2-Skimmers/2-Way Jandy Valve per line); 1 - 3" Suction Line (Floor Drain/ 2-Way Jandy Valve); 1 - 3" Return 8 Floor Outlets; 1 - Pentair IntelliFlo VS Prog Pump 240V/3HP (2013); 2 - Triton TR-140C Sand Filters Tandem Config (2013); 1 - In-line Chlorinator (2015). Misc - Pool Use: May to Sept; Turnovers: 2.5; Pump Operation: 23hrs

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    Re: Is this 40 yr old sand filter working?

    Dave,

    The so-called 'Screen' is integral part of what they call the 'Underdrain' Ref# 15. If you lose the 'Underdrain' .... just send the filter to Fred Sanford & Son!

    TJ
    60' x 30' IG concrete pool built in 1998. 2 - 2" Suction Line( 2-Skimmers/2-Way Jandy Valve per line); 1 - 3" Suction Line (Floor Drain/ 2-Way Jandy Valve); 1 - 3" Return 8 Floor Outlets; 1 - Pentair IntelliFlo VS Prog Pump 240V/3HP (2013); 2 - Triton TR-140C Sand Filters Tandem Config (2013); 1 - In-line Chlorinator (2015). Misc - Pool Use: May to Sept; Turnovers: 2.5; Pump Operation: 23hrs

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    Re: Is this 40 yr old sand filter working?

    I want to give an update about my diagnosis of this old sand filter. CNJ_EC has been extremely helpful and we had talked over the phone. I have not tried all the ideas I received from here, since water clarity has been okay by maintaining good chlorine level. But after 2 months from my original post, I finally got a chance to open the filter again and checked it more carefully.

    1) To test the filter, I poured DE to the skimmer with the pump and filter running. I did see cloudy water coming out of the return. So the filter seems not working properly.

    2) After opening the filter, I have a new major concern: I noticed two small holes in the multiport valve body. Please see pic link small holes in multiport valve. The bigger one is pointed by a screw driver. The other smaller one is in the compartment to the left of the bigger one. It seems they allow water to bypass the sand, and could explain why DE can come out of the returns. Anyone see similar holes in your Hayward multiport valves? What is the purpose? Should I try to seal them with epoxy putty and see if DE still comes out of the returns?

    the multiport valve model is Hayward SP711A-1. See pic here

    Thanks!
    Forest
    22,000 gals in-ground pool, 16 x 32 ft rectangle, Vinyl liner
    Hayward sand filter (model 225, tank diameter 22'', 50 gpm, yr 1975), Marathon 3/4 HP pump (model 1081, 3450 rpm)

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    Re: Is this 40 yr old sand filter working?

    I think you are missing a tubing, that allow to bleed the air.. But I am not an expert, so wait for others to confirm...
    8,400 gal Intex, 3K GPH pump, 16" sand filter, SWG CG-28669, TF100 test kit, speed stir, K-1766 Taylor salt test.

    The corner stone of TFP
    Pool School - Chlorine / CYA Chart

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    Re: Is this 40 yr old sand filter working?

    Thank you Piolin for the inputs. I was suspecting something like that too...
    Forest
    22,000 gals in-ground pool, 16 x 32 ft rectangle, Vinyl liner
    Hayward sand filter (model 225, tank diameter 22'', 50 gpm, yr 1975), Marathon 3/4 HP pump (model 1081, 3450 rpm)

  19. Back To Top    #19
    Piolin's Avatar
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    Re: Is this 40 yr old sand filter working?

    Your welcome, but remember to confirm that... I have one filter with the tubing but it's still in the box, waiting for winter to be installed
    8,400 gal Intex, 3K GPH pump, 16" sand filter, SWG CG-28669, TF100 test kit, speed stir, K-1766 Taylor salt test.

    The corner stone of TFP
    Pool School - Chlorine / CYA Chart

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    Re: Is this 40 yr old sand filter working?

    Hi Forest,

    Just got your msg. I examined the pic you posted and re-attached it here with some circled notations. From what I see - it appears that your spider gasket is deformed in a few places and I also see what appears to be 2 breaks(red circle with ?) along the compartment separator.

    Regarding the two holes .... I'll call Joey on Tuesday and ask about them ..... my guess is they're required. Keep in mind the SP711A is no longer in production so you might be hard pressed to find a replacement spider gasket or other parts. Maybe you should consider replacing the Filter/Valve Assembly at the end of the season ... you might be able to get a good discount on some close-outs.

    When you have a chance post a pic of the Valve Handle Assembly so I can see how each of the compartments line up.

    You have my # and regular email if you need to talk directly.


    Spider Gasket.jpg


    Tom
    60' x 30' IG concrete pool built in 1998. 2 - 2" Suction Line( 2-Skimmers/2-Way Jandy Valve per line); 1 - 3" Suction Line (Floor Drain/ 2-Way Jandy Valve); 1 - 3" Return 8 Floor Outlets; 1 - Pentair IntelliFlo VS Prog Pump 240V/3HP (2013); 2 - Triton TR-140C Sand Filters Tandem Config (2013); 1 - In-line Chlorinator (2015). Misc - Pool Use: May to Sept; Turnovers: 2.5; Pump Operation: 23hrs

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