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Thread: Correct Filter size

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    Correct Filter size

    We are considering replacing our 6 yr old sand filter with a DE filter because there is a lot of excavation going on behind our house. We have been having a very difficult time keeping our pool clear. We do not have an automatic cover (and we really can't afford one.) We currently have a 1Hp pump (SF=1.25) - came as part of the Pentair SuperFlo pump. The pump has 2" connections. We have 2 - 1 1/2" return lines, 1 - 1 1/2 skimmer line, and 1 - 2" floor drain line. We also have a 5 ton Heat Siphon heat pump. We are looking for a filter with ease of use that will keep the pool clear (the sand filter just doesn't seem to be doing a good job.- especially if we get any algae or dust). We just replaced the sand 2 years ago (bought sand at Leslies). Currently we are clearing up an algae issue, and yesterday I put skimmers socks over the returns (with gum bands) Any suggestions about socks on returns...?? . Anyway, to my main question, we are looking at the Pentair Quad DE 60, but I think it might be too big. According to my calculations we should need a 36 sq. ft. filter media. Will my current pump setup be able to adequately backwash the Quad 60? Any other suggestions are welcome.
    Heated (Electric Heat Pump) 16' X 32' in-ground, vinyl, 1HP pump, Sta-Rite Crystal Flo Sand filter (filter size = 3.1 sq. ft.) Installed in 2007. Has Floor drain, 1 skimmer, and 2 returns.

    Thanks

    Paul

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    Re: Correct Filter size

    I can't really answer your question, but just for reference, I have a 26 sq ft DE filter using a 1-1/2 HP motor with 1-1/2 inch PVC piping and about 12,500 gallons of pool water (spa is 500 gal but seperate system). The system works great if I take care of the pool (i.e. no algae and I vacuum into a leaf canister). I found out years ago that back flushing only removes about 2/3rds of the DE, so I rarely backflush, but instead, remove the filter housing top, remove the grids, and hose them off into the grass. I do this 3 or 4 times a year. With a clean filter, I start out at 5 psi and I clean the filter grids when I see 10-12 psi on the guage. I use approximately 5 coffee cans (of DE volume) to re-charge the filters. Old wet DE that I hose off can be continuously hosed into the grass (until practically invisible), but I pickup and throw away any clumps.

    I guess if I were buying a new DE filter system, I'd make sure that it was easy to take apart and put back together. I read that there are a few other people here that do a similar method of disassembly and hosing off the grids. You do need to be careful not to tear the grids on anything sharp. My grids typically last about 7-10 years, unless I tear one. My system is so old, that the filters are no longer made, so I won't mention a name.
    John (DIYer). Concrete, approximately 13,000 gallon in-ground pool with adjoining concrete spa. Approximately 40 years old. Hayward Super II pump for pool and legacy Anthony Sta-Rite bronze pump CF6 for spa, VA-26 filter,(2 sets), Rheem propane heater for spa. HASA Liquidator for pool.

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    Re: Correct Filter size

    No filter of any type will clear a pool of live algae. Do not expect a DE to do any better than a sand filter for that....it won't.

    It is a fairly common misconception that pool water murkiness is attributable to the filter when, more often than not, it is a water chemistry (chlorine) issue.

    I know that is not the question you asked but it must be considered carefully. Changing the filter type rarely has much affect on water clarity unless there is something mechanically faulty with your current filter.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Correct Filter size

    I believe that sand filters are relatively simple. Ours however, seems to let some of the particulate back into the pool. You can't see it coming back in, but you can see it as it collects on the bottom of the pool. I recently replaced the gasket ( it comes attached to the diverter), as i thought this might be why some of the particulate keeps coming back into the pool. I don't get sand in the pool. Also of note is that the pressure gauge barely moves ( I just replaced it also). It continuously reads between 18 and 20 psi.
    Heated (Electric Heat Pump) 16' X 32' in-ground, vinyl, 1HP pump, Sta-Rite Crystal Flo Sand filter (filter size = 3.1 sq. ft.) Installed in 2007. Has Floor drain, 1 skimmer, and 2 returns.

    Thanks

    Paul

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    Re: Correct Filter size

    I agree with duraleigh that changing filters is the not the next thing to try yet.

    You may want to try this: http://www.troublefreepool.com/my-sa...-it-t7626.html
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Correct Filter size

    You can't see it coming back in, but you can see it as it collects on the bottom of the pool.
    Paul, that is a very common description of dead algae collecting on the bottom of your pool....indicating that you have some live algae that exists in your pool. If that's the cause the DE filter will show no improvement. The issue is that live (invisible) algae is being partially but not completely killed and the "dead bodies" become visible on your pool floor as they accumulate in the crevices and low spots. This whole process takes place in your pool and not in the filter. I still suspect your issues are chemistry and not mechanical filtration.

    That said, have you opened up the filter to see what the sand bed looks like? I doubt that there are any issues with it since you put in new sand but it might be worth doing. The sand bed should be inspected and cleaned at least biannually anyway (annual is better) so it would give you an opportunity to do that as well.

    I am not suggesting chemistry issues solely as an opinion but rather based on the 9 years or so of being on these forums and seeing very similar reports....lot's of them.

    A complete set of test results is often very revealing....can you post those up?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Correct Filter size

    I was told by the pool store that the 3" pucks provide the "Free" chlorine. If I am only using liquid chlorine, where does the FC come from? Do borates contribute to FC, as I have not yet started adding borax? Also, I am still wondering what would cause my filter PSI to remain so stable (18-20 psi), even when vacuuming heavy algae?
    Heated (Electric Heat Pump) 16' X 32' in-ground, vinyl, 1HP pump, Sta-Rite Crystal Flo Sand filter (filter size = 3.1 sq. ft.) Installed in 2007. Has Floor drain, 1 skimmer, and 2 returns.

    Thanks

    Paul

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    Mod Squad jblizzle's Avatar
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    Re: Correct Filter size

    Welcome to TFP!!!

    You have to stay out of the pool stores ... they are full of bad advice.

    chlorine = chlorine = chlorine does not matter the source. Tablets add FC and CYA and lower the pH. Liquid Chlorine adds FC and a little salt.

    Ignore borates for now as you need to learn the import chemistry first (they have nothing to do with FC).

    I think you should clean the sand as the link linen provided explains and then read more Pool School:
    ABCs of Water Chemistry
    Recommended Pool Chemicals
    How to Chlorinate Your Pool

    And get one of the Recommended Test Kits on order ASAP.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
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    Re: Correct Filter size

    paulyd,

    reading your last post, I would suggest you need to learn a lot more about pool water chemistry before you spend money on a new filter. It's appears you don't know if your chemistry is adequate to prevent algae and that convinces me even more that your issues are likely chemistry issues and not filtration.

    Please start by reading "The ABC's of Pool Water Chemistry" up in Pool School
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Correct Filter size

    I'm on it. I've got the TF100 and have been getting my chemistry in line since we drained the pool a week or so ago. I have the CYA at around 40, the TA at around 100, the PH at 7.6, the FC at 20 and the CC is currently at 1.5 (but hopefully less in the a.m. as we are trying to kill the algae bloom that we let get ahead of us.) I thought I had enough FC to prevent an algae bloom, but since my cya was low ( I brought it up slowly as it can take a week to fully dissolve/register) the FC must have went too low also. Thanks for the advice. I really appreciate it.
    Heated (Electric Heat Pump) 16' X 32' in-ground, vinyl, 1HP pump, Sta-Rite Crystal Flo Sand filter (filter size = 3.1 sq. ft.) Installed in 2007. Has Floor drain, 1 skimmer, and 2 returns.

    Thanks

    Paul

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    Re: Correct Filter size

    Well, your test results indicate that you are more aware of your chemistry than seemed to be from your earlier post.

    That said, because you are working on an algae bloom, that further suggests your pool murkiness is caused by algae and not a problem with filtration.

    Let's go back to the beginning.....since you already had algae and your pool was (I assume) murky from that, why do you think the filter is not performing properly? I'm just a bit confused but we'll get it sorted out.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Correct Filter size

    I'll bet you will be pleasantly surprised about your filter performance once you have a good water balance. This of course after you have killed and filtered all the algae.
    TFP Moderator
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    ABC's Of Pool Chemistry, Test Kits, SLAM Your Pool
    28K Gal IG FreeForm, CLI Quartz, Pentair 36"SF & VS Pump, Dolphin M5, Rheem

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    Re: Correct Filter size

    Duraleigh,

    Last night I opened up the sand filter and put a garden hose in while I reached in a stirred up the sand. I did a very good job of loosening up most of the sand (even around the latterals). Then I backwashed, rinsed, and backwashed again. Then I banged on the side of the filter tank with rubber mallet. Perhaps I am expecting too much from my filter. Once the algae is dead and the CC level drops below .5, I'll give it week. If it doesn't clear up in a week, then I can safely assume that filter isn't filtering properly...?? The pool is a little better than yesterday. I tested the water again this morning (FC was 19 last night at dusk and 15 first thing this morning) and added 2 gals. of 12.5% chlorine. An hour or so after adding the chlorine, I tested again. The numbers really look good (except for the CC since we are still killing algae). The numbers are: FC=25, CC+1.5, CYA= 40, TA=110, PH=7.8, CH=340(our city water has tons of calcium, so I can't really do anything about this).

    Again, thanks for your help!

    Paul
    Heated (Electric Heat Pump) 16' X 32' in-ground, vinyl, 1HP pump, Sta-Rite Crystal Flo Sand filter (filter size = 3.1 sq. ft.) Installed in 2007. Has Floor drain, 1 skimmer, and 2 returns.

    Thanks

    Paul

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    linen's Avatar
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    Re: Correct Filter size

    Quote Originally Posted by paulyd
    If it doesn't clear up in a week, then I can safely assume that filter isn't filtering properly...??
    After you pass the OCLT and your CC is less than 0.5 ppm, then using some pool filter DE can help getting fine particles trapped in the sand filter. See: http://www.troublefreepool.com/pool-..._a_sand_filter Usually this is only needed for a short time (couple of days) to speed up the cleaning process.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Correct Filter size

    Linen,

    I tried using DE in sand filter once before, but it seemed as though the DE was coming back into pool. Is this common?
    Heated (Electric Heat Pump) 16' X 32' in-ground, vinyl, 1HP pump, Sta-Rite Crystal Flo Sand filter (filter size = 3.1 sq. ft.) Installed in 2007. Has Floor drain, 1 skimmer, and 2 returns.

    Thanks

    Paul

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    Mod Squad jblizzle's Avatar
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    Re: Correct Filter size

    Quote Originally Posted by paulyd
    Linen,

    I tried using DE in sand filter once before, but it seemed as though the DE was coming back into pool. Is this common?
    No. That would indicate a problem with either your backwash valve, the sand being channeled, or a lateral in the filter broken (although that usually shows sand back to the pool).
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  17. Back To Top    #17

    Re: Correct Filter size

    Hmm, Maybe I'll try adding a little DE again. We'll see how it looks tomorrow
    Heated (Electric Heat Pump) 16' X 32' in-ground, vinyl, 1HP pump, Sta-Rite Crystal Flo Sand filter (filter size = 3.1 sq. ft.) Installed in 2007. Has Floor drain, 1 skimmer, and 2 returns.

    Thanks

    Paul

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    Re: Correct Filter size

    Quote Originally Posted by paulyd
    Hmm, Maybe I'll try adding a little DE again. We'll see how it looks tomorrow
    Just make sure you use pool filter DE. We recently had an episode with someone using food grade and it was a mess.
    TFP Moderator
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    ABC's Of Pool Chemistry, Test Kits, SLAM Your Pool
    28K Gal IG FreeForm, CLI Quartz, Pentair 36"SF & VS Pump, Dolphin M5, Rheem

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