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Thread: Filter pressure readings.

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    Filter pressure readings.

    Odd things seem to be happening. Start the pump (9:30am)and pressure goes to 14/15lbs and stays there. After awhile (12pm), now reads 25lbs; later (3pm) now 33lbs). I started with a clean filter (see my post"new products"). When I start the pump again; back to normal 15/14 and the cycle repeats itself. The pool is not getting cleaner. Chemicals are Ok but now Chlorine is low, I'm debating if I should take the filter apart again. Any ideas would be appreciated.
    Redding Connecticut, Wagner pool 50k gal. cement. DE filter requires 9 pounds of DE to restore. 9ft deep kidney shaped.

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    Mod Squad Bama Rambler's Avatar
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    Re: Filter pressure readings.

    Post a full set of test results and how you got them.
    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 pressure readings.

    bama is asking for test results very probably because he suspects (as do I) that you have some algae in the pool....even though you cant see it. Your chlorine was adequate but is now low because the algae has consumed it. The dead algae is clogging your filter causing the psi to rise.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Filter pressure readings.

    OK will test again today, thanks. Still don't understand why it powers up with good readings?
    Redding Connecticut, Wagner pool 50k gal. cement. DE filter requires 9 pounds of DE to restore. 9ft deep kidney shaped.

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    Mod Squad Bama Rambler's Avatar
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    Re: Filter pressure readings.

    Also tell us more about your equipment.

    If it takes 9 lbs of DE that's one big filter. What size is your pump?

    I do suspect that you have something growing in there.

    There have been reports of DE filters doing that before.
    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 pressure readings.

    The filter is a Hayward (large 72sq ft). The pump is a horse and a half; pumps very well. As I mentioned I started off with a cleaned filter (done by a pool place). Maybe an algacide as well as strong shock is called for. Can they be done at the same time?
    Redding Connecticut, Wagner pool 50k gal. cement. DE filter requires 9 pounds of DE to restore. 9ft deep kidney shaped.

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    Re: Filter pressure readings.

    Still don't understand why it powers up with good readings?
    If it is filtering dead algae (very, very fine particles) a coating of debris can form on top of the sand bed, causing the psi to rise.

    When you shut off/turn on the pump, that "bump" in the water flow dislodges that debris coating temporarily causing the psi to go back more towards normal. It resettles pretty quickly and you have the same issue each time.

    Don't waste your time or money on algaecides and learn how to shock the pool properly up in Pool School. The test results is your first step towards getting your pool clear.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Mod Squad Bama Rambler's Avatar
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    Re: Filter pressure readings.

    As Dave said, don't waste your time or money on algaecides. Shocking is what's most likely going to be called for.

    Have you backwashed the filter lately?
    If you do only add about 80% of the original amount of DE back to it afterwards.
    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 pressure readings.

    Thanks again for the insight. I throughly backwashed the filter again. I added 9 pounds of DE. I weighed it exactly on a digital scale. I added 5 gallons of liquid clorine (12 1/2 %). Pool pressure on starting was about 15lbs, then creeped up t0 17. Readings now are: FC way over 5 (thats as high as my measure goes); PH 7.5, TA 70, CYA 30, CH 120. Have I missed anything? Your "bump idea" at closing seems to make perfect sense. That's the way it behaves. Any other advice is always welcome and appreciated.
    Redding Connecticut, Wagner pool 50k gal. cement. DE filter requires 9 pounds of DE to restore. 9ft deep kidney shaped.

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    Mod Squad Bama Rambler's Avatar
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    Re: Filter pressure readings.

    You need a good test kit.

    What does the water look like?
    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 pressure readings.

    Now almost 24 hours after I put in the chlorine, water not clear but better. Has a green cloudy hue. Chlorine still high and the rest good. Pressure climbing in the twenties. I expect to backwash soon. I'll order the test kit.
    Redding Connecticut, Wagner pool 50k gal. cement. DE filter requires 9 pounds of DE to restore. 9ft deep kidney shaped.

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    Re: Filter pressure readings.

    As Bama said before, after your next backwash only add ~7 lbs of DE (this assumes that you're letting the pressure rise 8- 10 psi before backwashing).
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

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