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Thread: Using two cartridge filters

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    Using two cartridge filters

    Hi I am new to this site. I have had an Intex 12' - 3' pool for 2 years and I am upgrading to a 15' - 4' Intex pool. I think that the new pool comes with a 1000 gph type A cartridge filter just like the 12' pool. I will now have two 1000 gph Type A filters. Has anyone connected two filters in parallel. I know the flow will not double but the filter area will. I am not sure of the surface area difference between a type A and type B filter. I might just go buy the 2500 B type cartridge filter, cut the new holes before I fill the pool, for $100.00 but money is tight.

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    Mod Squad zea3's Avatar
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    Re: Using two cartridge filters

    A second filter in series really won't do much, however if you can add a "T" to the intake line and then plumb a filter/pump to each side that will increase your filtration. You could rig up the return from one of the pumps to use as a fountain. Take a look at some of the other intex threads listed here for more ideas.
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    Re: Using two cartridge filters

    Welcome to tfp, 1380ken

    Some people have tried this, I can't find the link. Usually it is better to have two distinct water loops, so both filters can be more effective verses bringing their flow together out side of the pool since each has it's own pump. If I recall, a couple of posters just put the second pump's tubes over the edge of the pool.

    If you are looking to upgrade the filter, I would not go for a intex cartridge (they're still fairly ineffective from reports), but instead a intex sand filter such as the 1600 gpm, which has gotten fairly good reports.
    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: Using two cartridge filters

    I have looked at the sand filters but the only real advantage is the low maintenance. I really don't mind doing pool maintenance, I wouldn't mind cleaning the filters every other day. The cartridge filters filter out smaller particles than the sand filters. My friend gave me an old Hayward DE filter with a 3/4 hp pump but I do not want to over filter the pool and waste electricity, plus I think the bearings are going on the pump. I have also heard if you have too much flow the pool will be a wirlpool and the larger particals in the pool will have too much velocity and not be sucked into the filter intake.

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    Re: Using two cartridge filters

    What they are telling you is that the Intex cartridge filters are not like normal cartridge filters and do not filter as good as a sand filter. In your case, a sand filter is an upgrade.

    Don't knock sand filters. I have a 44,000 gallon pool with some of the clearest water you've ever seen, and it's filtered by sand. Never covered, ever. The filter does all the work. And I only have 1 skimmer!
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    Re: Using two cartridge filters

    I know the flow will not double but the filter area will.
    OP seems to be suggesting filters in parallel, not series, and I see an advantage in that.....just like he says, his filter area doubles. I suppose OP could get clever and plumb them so he can bypass one or the other allowing him to take one offline for repair/cleaning.....(that's a stretch) but I do see an advantage in using both filters.
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    Re: Using two cartridge filters

    So what I hear is that the Intex cartridge filter is not a quality filter and will not filter down to 10 microns. I agree that a cartridge filter may not be as practical as a sand filter for a 44000 gallon pool but my pool is around 6000 gallons. In theory a cartridge filter will filter out smaller particles than a sand filter? Is this correct? Is it just a matter of using a different cartridge in the Intex filter?

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    Re: Using two cartridge filters

    In theory a cartridge filter will filter out smaller particles than a sand filter? Is this correct?
    It's correct but not particularly relevant. For most, it is impossible to tell any difference in water clarity regardless of the filter used......here's a pic of my water (7') with a sand filter....no additives of any kind just plain ole' sand that is now 8 years old.[attachment=0:35tmgwh0]DSC00049.JPG[/attachment:35tmgwh0]
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    Re: Using two cartridge filters

    Quote Originally Posted by 1380ken
    So what I hear is that the Intex cartridge filter is not a quality filter and will not filter down to 10 microns. I agree that a cartridge filter may not be as practical as a sand filter for a 44000 gallon pool but my pool is around 6000 gallons. In theory a cartridge filter will filter out smaller particles than a sand filter? Is this correct? Is it just a matter of using a different cartridge in the Intex filter?
    There are pools the size of mine with carts. Your first point is the Intex is not a quality filter, there's your clue. Many folks here with pools like yours have reported a significant improvement when switching from the Intex carts to a sand filter. The inground pools tend to have a higher quality cartridge filter than what comes with the above ground kits.

    I'll let some of the AGP folks who have converted chime in. They can give you first-hand experience.
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    Re: Using two cartridge filters

    Quote Originally Posted by 1380ken
    So what I hear is that the Intex cartridge filter is not a quality filter and will not filter down to 10 microns.
    That is my experience.

    Quote Originally Posted by 1380ken
    In theory a cartridge filter will filter out smaller particles than a sand filter? Is this correct?
    This is correct, though not the intex cartridge (again from my observations, though I have not done a study on particle size, etc.).

    Quote Originally Posted by 1380ken
    Is it just a matter of using a different cartridge in the Intex filter?
    Maybe, I know some in here have discussed other brands, and the improvement they see with them. I am guessing here since I did not try other filter brands, but the pump in these intex filters may not handle much "tighter" filter media well...which might be why intex chose such a poor filter media. I know that when they get just a little dirty, the flow rate drops quickly...much quicker than more typical cartridge filters (could be due to surface area). I think intex was trying to make a cheap disposable filter/pump (and they succeeded),but that required compromise, including filter performance.
    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: Using two cartridge filters

    There are some reusable cartridges that will fit inside an Intex filter. The reusable feature is nice, but they don't filter very much better. To get an actually good cartridge filter you need a much larger filter, which won't fit inside the Intex unit.

    The most affordable choice is to get the larger of the Intex sand filters. That does a very good job and is reasonably priced (compared to all of the other options).
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    Re: Using two cartridge filters

    Quote Originally Posted by JasonLion
    The most affordable choice is to get the larger of the Intex sand filters. That does a very good job and is reasonably priced (compared to all of the other options).
    Although the larger intex 2650 gph sand filter would also be good, I think for your pool you can also consider the 1600 gph sand filter (I set that one up on my neighbors 16' intex) and, IMO, is a good fit for that size (5000 gallons), since it turns his pool over in about 4 hours and works decently with my vacuum head when he borrows it.
    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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