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Thread: Sand Filter - just not cutting it?

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    Sand Filter - just not cutting it?

    Figured I'd start a new post for this topic. I just got over an algae problem as detailed here: hi-everyone-new-here-t21008.html

    Now the next problem is the cloudy paticulate matter that's still in the pool. I've had the filter on 24/7 for a few days and it hasn't started clearing up at all. The last time I was able to get the pool totally clear was by using a flocculant and vaccuming to waste. It would appear that my sand filter just can't cut out the smaller particles.

    So the question is, what to do?

    Pool is about 3-4 years (I think) old so the sand shouldn't have to be replaced, right?
    Should I add a secondary filter - perhaps a canister filter for final polishing?

    I would hate to have to resort to a montly flocculant treatment since I got my first water bill and it's $60 a month....
    33ft / 48" AG - 1.5HP 70GPM - Haywood sand filter - approx 3 years old.

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    frustratedpoolmom's Avatar
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    Re: Sand Filter - just not cutting it?

    Try a little DE in the sand filter:
    http://www.troublefreepool.com/pool-..._a_sand_filter

    Or clarifier....
    Helpful links: Pool School; CYA/Chlorine Chart
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    JasonLion's Avatar
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    Re: Sand Filter - just not cutting it?

    There is nothing wrong with your sand filter. Your problem is that the algae isn't all dead yet, or at least it wasn't on Saturday the last time you posted on that other topic. Just having "measurable FC levels" isn't enough. You have to maintain high FC levels until the algae is all dead. As long as there is live algae in the pool, no filter can ever possibly keep up. Take a look at How To Shock Your Pool over in Pool School. My guess is that you haven't been using nearly enough chlorine.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Sand Filter - just not cutting it?

    You could be right on the "not adding enough" chlorine. That said, I was under the impression that once the levels were up high enough and the algae wasn't growing on any surfaces that it was effectively dead and at very least the particulate matter in the water column would start to reduce.

    I'll get back on target.
    33ft / 48" AG - 1.5HP 70GPM - Haywood sand filter - approx 3 years old.

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    Re: Sand Filter - just not cutting it?

    Additionally, brushing can break apart the algae into particles too small for sand to capture. The addition of the DE will help. Expect the pressure to rise shortly there after meaning it's time to backwash.

    Scott
    Owner of - PoolGuyNJ LLC
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    Re: Sand Filter - just not cutting it?

    I have the same problem and I find it quicker to use floc after the algae is dead. When the algae is dead, I get the pool to shock level again and add the floc, run the filter on recirculate for 2 hours, and then shut off the pump for two days. You will want your water level high when you vacuum to waste.

    Right now the junk is on the bottom and the water is clear. Time to send it to waste.

    It would take me 7-10 days, messing with backwashing, without using the floc. And adding DE to the filter would just raise the pressure too fast.

    I do use the skimmer socks and sometimes add DE, after the water is free of the opening algae.
    Joe

    21k IG vinyl, 300 lb. sand filter, 1hp pump, Polaris 280 cleaner, 3/4hp booster pump, 240sq ft Fafco solar, Liquidator

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    Re: Sand Filter - just not cutting it?

    So now after a week or so of keeping the chlorine level high, brushing, no recurrance of algae and consistent backwashing/running the pump for 12 hours a day.... STILL cloudy.

    That said - I'm looking into my original idea of adding a secondary canister filter after the sand filter.

    The discussion on flow rates goes as follows:

    I have a 70GPM pump.
    My sand filter is rated at 50GPM
    Question 1: Is that a problem? IE: is having "too much" flow possibly causing an inefficiency?

    I'm contemplating a small canister filter to run after the sand filter (I was looking at this one: http://cgi.ebay.com/Hayward-C225-Micro- ... 56393773e0) $80 isn't bad...
    Now, I get that this filter on it's own is waaaay too small to run on this pool, but I'm wondering if it might provide a lower micron filtration level that will help polish the pool.

    That said, it's rated for 20 GPM.... is that going to:

    A: SIGNIFICANTLY restrict the flow to the pool
    B: Potentially cause backpressure problems with the pump

    Would it make sense to possibly split the output from the sand filter and run only 'some' of the flow through this filter?

    Any suggestions appreciated...
    33ft / 48" AG - 1.5HP 70GPM - Haywood sand filter - approx 3 years old.

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    Mod Squad Bama Rambler's Avatar
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    Re: Sand Filter - just not cutting it?

    First let me say that I recommend changing your filter out to a DE filter if you just have to do something. They provide the finest filtration.

    Installing the filter you linked to in the main line will restrict flow to the point of being a problem.
    You could install it as a side stream filter but the amount of time it would take to filter the water would be great and as it got dirtier the water would bypass it in the other stream.
    Dave J. TFP Moderator
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    Re: Sand Filter - just not cutting it?

    I would use the floc before messing with adding more filters. You mentioned that is how you cleared it in the past.

    I just noticed that this is an AG pool. Note sure how well the stuff on the bottom of the pool is getting suspended, so the skimmer can send it to the filter. Your skimmer is just touching the top 4-6 inches of water.

    I use floc on my pool,,it works great when you have a sand filter!
    Joe

    21k IG vinyl, 300 lb. sand filter, 1hp pump, Polaris 280 cleaner, 3/4hp booster pump, 240sq ft Fafco solar, Liquidator

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    Re: Sand Filter - just not cutting it?

    Yeah - I know it works great. BUUUUUT>>>>

    2 things:

    1 - the only source I have locally is for pool store bought buckets. A bucket costs $30 ish. and it's a 1 time application. That plus 70 GPM of vaccum to waste on a 33ft round pool = lots of wasted (expensive) water..

    Just looking for a plug and play solution that doesn't involve periodically wasting 2000 gallons of water and $30 worth of ALUM.

    Is there a cheaper source for flocculants?
    33ft / 48" AG - 1.5HP 70GPM - Haywood sand filter - approx 3 years old.

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    Re: Sand Filter - just not cutting it?

    Strange to think, that during a Google search for this topic my thread came up...

    Still having this problem. Only way I can fix it is to floc and vac to waste... Done it once already - still cloudy after a week of balanced pH, Alk, Chlorine levels....

    Still looking for bulk flocculant source...

    Anyone?
    33ft / 48" AG - 1.5HP 70GPM - Haywood sand filter - approx 3 years old.

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    Re: Sand Filter - just not cutting it?

    I have never had a problem clearing my pool after the shock process. Been through it three times since moving into the house (why is another discussion) and it has cleared within a few days every time.

    Post a picture of what you see, but my guess is the water looks a litte translucent, kind of milky?

    Have you tried adding DE through the skimmer? (sorry if you did and I missed it)
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II TR-100 Sand Filter, CircuPool RG 60 Plus SWG, TF-100 test kit
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    JasonLion's Avatar
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    Re: Sand Filter - just not cutting it?

    Every now and then there might be some reason to use floc, but if you have any reason to use floc regularly then something is broken. Your sand filter is undersized for your pump. That might have caused it to become channeled. Try following the instructions in this post and see if that helps.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Sand Filter - just not cutting it?

    The use of flocculants sometimes works and frequently doesn't. For every testimonial we see in favor of them on the forum we see at least as many negative reports....probably more.

    So, it is not a "one size fits all" solution.

    Joe and James, here's a picture of my robot in 7 feet of water. I have a sand filter and have never used a flocculant or clarifier in the life of the pool. Your equipment may not be sized correctly for it to work for you (both the filters you mention are too small...you need one rated at least 80-90 gpm for that pump) but sand filters do work in a correctly sized system.
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    Re: Sand Filter - just not cutting it?

    Duraleigh, I thought my sand filter was big!
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II TR-100 Sand Filter, CircuPool RG 60 Plus SWG, TF-100 test kit
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