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Thread: filtering dead algae

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    filtering dead algae

    Will my sand filter clear the cloudy (I assume it is dead algae) water? I have been told the particles are too small for the sand to remove. I do not want to put a flocculant in it, if possible. My filter is a TR 100 with 4.9 ft of surface area, I think 100 gpm (label is hard to read), with a 1HP pump?

    This system was installed 40+ years ago by a relative that is now deceased.

    My water is now turning green again so am back to shocking.....I backwashed, then refilled, then it RAINED, a lot. So I am thinking the level went up to areas that had algae before and not removed. We had so much rain in the spring that the pool overflowed.

    Friday and Sat the pool was cloudy, I noticed late Sun what appeared to be some new algae and my CL was correct for maintenance levels. Oh we go again, back to shock

    And of course, my cya is spastic (or I am! not unlikely) Last weekend it was 50, today, with dilution techniques) it was at the top of the tube and I could still see the dot! Which would put it at less than 20.

    I shocked for 50. Good grief, I go from a cya of 100 at the first of the season and now it is almost nothing.

    I have also read that every molecule, so to spea, of algae muct be removed from the surfaces of the pool. That is going to be near impossible with this pool.

    The surfaces are in no way smooth, the steps are home made of PVC with stepping stones for the steps of the ladder. The plumbing is a pvc pipe down to the bottom of the deep end with a one way valve. There is a side pipe with a valve for connecting the vacumn.

    The return is also a pvc pipe dropped over the edge of the pool. In other words, there are a million+ crevices for algae to hide. Is this hopeless for the BBB method?

    My original plan was to use scuba to scrub the surfaces when I could see, after the cloudiness lightened up, but I still could never get every nook, cranny, seam and crevice.
    60+ year old 50'x15' IG 30K gal LRB coated cinderblock with no drains, no skimmers, all plumbing external, spent the last 3 years chipping to substrate to patch, repair and coat with a pool sealing product from Sanitred by myself to hopefully eliminate 2 months yearly getting the antique pool ready. The original "cement pond"

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    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: filtering dead algae

    The sand filter will clear up the water, but only if the algae is all dead. It might take it a week, or more, but you should see a visible improvement from day to day.

    But if you let the FC level go too low and the algae got started again, then you need to go back to shocking.

    You don't need to brush every single crevice. But if the crevices are too deep they may form spots with bad circulation that the algae can hide in. Pebbles embedded in plaster (for example) is fine, but a narrow crevice between two stones that goes in several inches is going to cause problems.
    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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