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Thread: Filter too small says Mr Honest Pool Store Guy.....

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    Filter too small says Mr Honest Pool Store Guy.....

    Hey Folks,
    When replacing my DE Filter years ago I replaced it with a 90 sq Ft Hayward Cartridge filter after looking at the in-store brochures. A year or so ago when I had my pool resurfaced (guniite to fiberglass) they tried to convince me I needed to get a larger filter. I have a 15kgal in ground pool with a 1.5Hp hayward pump. I can get replacement filters @ Lowes for 50$ so its easy to keep extras around and I just swap out a clean one for the dirty ones. So are they right? Is my filter too small?

    If so can anyone point me to the calculations so I can figure out the right size?

    Thanks in Advance!
    16k Gal fiberglass over plaster
    Hayward CX900RE
    Leslie's HydramaxII 1.0Hp pump
    Polaris 280

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    Mod Squad Bama Rambler's Avatar
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    Re: Filter too small says Mr Honest Pool Store Guy.....

    90 sqft is small for that pool but all that means is that you have to clean the filter more often and it has more head loss than a larger filter would have. If you ever have to replace it you should go with at least a 200 sqft.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    JasonLion's Avatar
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    Re: Filter too small says Mr Honest Pool Store Guy.....

    I agree with Bama. 90sqft is smaller than what I would recommend, but is certainly large enough to work without any issues beyond needing to clean the filter more often than you would need to clean a larger filter.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Filter too small says Mr Honest Pool Store Guy.....

    Thanks Guys! So how would you calculate the "right" size filter?

    Also I've been having cloudiness issues that I believe my filter is missing. Its a while powder that I rinsed off the filter cartridge.
    I been fixing it slowly using a flocculant, disabling my pool sweep and vacuuming out of the pool system directly to sewer drain (as I believe it passes through my filter).
    Could be a side effect of having too small a filter? Higher pressure forcing smaller particulate through the filter material? I've seen some specs that say cartridge filters go down to 20microns but nothing from Haward (or Unicel) specifically.

    Has anybody discussed going to a 5micron filter? Watts makes them that could handle pool flow rates (http://www.watts.com/pages/_products_de ... p?pid=6013) and a 5 micron filter is about 50$.
    Thoughts?
    16k Gal fiberglass over plaster
    Hayward CX900RE
    Leslie's HydramaxII 1.0Hp pump
    Polaris 280

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    JasonLion's Avatar
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    Re: Filter too small says Mr Honest Pool Store Guy.....

    That sounds like calcium clouding. Calcium clouding particles are so small that they will pass through any filter out there. If you post a complete set of levels I can get a better idea if it is calcium clouding or not, and if it is what to do about it.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Lershac's Avatar
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    Re: Filter too small says Mr Honest Pool Store Guy.....

    Calculating the right size filter is easy. Get the biggest one you can afford. I am lazy, so I only want to clean once a year.
    (DIY):16K Gal 20X30 rectangular IG Gunite, w/spa, CCP 520 filter,2 Pentair VS pumps, 400KBTU Pentair gas heater, Heat Pump for cooling, **update5.25.2013** added an intellichem with acid pump that will control existing SWG. My Build Thread Here

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    Mod Squad Bama Rambler's Avatar
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    Re: Filter too small says Mr Honest Pool Store Guy.....

    I've thought about putting a 1 mic filter after my sand filter but I haven't convinced myself that it would be worth it.

    A good set of test results would help us too.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Filter too small says Mr Honest Pool Store Guy.....

    Calcium clouding... Calcium is definitely what the material looks like after it dries up.

    The manual for my Taylor test kit mentioned as well. I need to replace some of my reagents so I can retest. I'll do that and post results later today. BTW THANKS for having an awesome site!!!
    Your forum has been a big help.

    Numbers I got from last night:
    Total Alkalinity:150 (it comes out of my tap @ 140)
    PH:7.5
    TC:2.5
    CC:0
    Calcium Hardness:140? (need to retest. Ran out of reagents)
    CYA: 30
    Temp:80

    WRT to that filter: I found the housing avail on the net for 499$ http://www.uswatersystems.com/shop/prod ... 2d150.html
    The filters are made by Watts who seem to make industrial filters. Not sure how long they've been around.

    Has anyone discussed a post vacuum only filter to catch the stuff the cartridge can't catch? Insert it post main filter so it doesn't get clogged with the larger stuff. Or has anybody found good cartridge replacements that have a smaller filter spec?

    Thanks!
    16k Gal fiberglass over plaster
    Hayward CX900RE
    Leslie's HydramaxII 1.0Hp pump
    Polaris 280

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    Re: Filter too small says Mr Honest Pool Store Guy.....

    Here's the latest. Let me know if you folks think its Calcium related based on my numbers.
    Numbers I got from last night:
    TA:180 (it comes out of my tap @ 140)
    PH:7.6
    TC:2.5
    CC:0
    Calcium Hardness:180
    CYA: 40
    Temp:80

    I rechecked the numbers against Taylor's SI using their Watergram Calculator. According to that my SI is .2 which should still shouldn't cause cloudiness due to Ca. Has anybody used the Watergram in the past with luck?

    Also since I've killed the Polaris and let stuff settle there's a ton of particulate in the deep end I can vacuum out and the water is much clearer.

    So my guess is it was something EXTRA in leslie's PowerPowderPlus (CaHipo) which won't be an issue as I'll only be chlorinating with liquid going forward.

    A few more questions:
    1. Taylor mentions a difference in TA numbers based on CYA as well. (Tactual = TAmeasured - CYA*.33), do you folks use this calc?
    2. Shocking question... So alot of you folks seem to shock pretty often. Do you use Thiosulfate to get the FC down to swimmable numbers or do you just let it drift down with time/use?
    3. My TAmeasured is too high. According to the the Taylor K2006 manual if I add ~3quarts of Muriatic it will take care of it. I also notice from the PoolCalculator to go from 7.6 to 7.2 its says I should add ~3quarts of Muriatic. Do you folks think they are doing a different calculation, since the Table didn't ask what starting PH was?

    Again Thanks A TON in Advance!
    16k Gal fiberglass over plaster
    Hayward CX900RE
    Leslie's HydramaxII 1.0Hp pump
    Polaris 280

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    Mod Squad Bama Rambler's Avatar
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    Re: Filter too small says Mr Honest Pool Store Guy.....

    I seriously doubt that it's calcium clouding.
    It looks like your FC is too low for your CYA level. That's probably your problem.

    If you'll notice, the only people around here that shock are the new people coming in with problems. Most of us that have been around rarely, if ever, shock. But to answer your question, the sun is very good at lowering the FC level and besides you can swim up to shock level for your CYA.

    We never recommend adding acid without knowing what your pH is. If your pH was 6 imagine what would happen to it if you added 3 qts of muriatic acid to the pool.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Filter too small says Mr Honest Pool Store Guy.....

    Any other input on my other questions?
    1. Any merit wrt TAmeasured vs. Actual based on CYA?
    2. Any merit to the Taylor SaturationIndex(SI)/Watergram Tool?

    Thanks
    16k Gal fiberglass over plaster
    Hayward CX900RE
    Leslie's HydramaxII 1.0Hp pump
    Polaris 280

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