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Thread: Old filter sand - up close!

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    Old filter sand - up close!

    I think it's time for new filter sand? My PSI climbs from 15 to 20-25 in a matter of days, and my water is quite clean. I just did the deep clean last night and noticed my sand has been warn down into tiny smooth spheres! I don't know how old it is but I brought a sample into work to take a look at under the scope and share with you guys here.











    On a side note, what does the air relief tube do? I pulled it out to get the diffuser off last night abut just kinda stuck it back in when I was done. Where is the end of the tube supposed to go?
    Last edited by chjade84; 05-09-2014 at 11:25 AM. Reason: Added better quality photos
    22,000 gallon in-ground kidney-ish shape: 1 HP pump and Triton TR60 sand filter. NEW: Dolphin Nautilus robot! :)

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    Re: Old filter sand - up close!

    What would be awesome is what new sand looks like just to get a comparison

    14,750 GAL IG Fiberglass (16 x 33) NE Ohio || Jandy 1HP 2 speed Pump || Waterco MultiCyclone 16 Centrifugal pre-filter (removed due to not working with sand filter) || 30" 575 Lb. Sand Filter || AquaCal 140K BTU Heat Pump || Solar Cover || Inter-fab Adrenaline Slide || GLI Monsoon Solar Cover Reel || K-2006C Test Kit || BBB with Liquid Chlorine Stenner Injection || Rayner Mighty Mesh Winter Cover

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    Re: Old filter sand - up close!

    Quote Originally Posted by toofast View Post
    What would be awesome is what new sand looks like just to get a comparison

    Sent from my DROID RAZR HD using Tapatalk
    Yes it would! When I get some, I'll make sure to add it!
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    Re: Old filter sand - up close!

    We never suggest changing the sand. It comes to you millions of years old already so 20 years in a pool has little affect.
    My PSI climbs from 15 to 20-25 in a matter of days, and my water is quite clean.
    That simply means your sand is catching particles and the particles are adding resistance to your system.

    Posting a complete set of test results is the first step but your water is not perfectly clear or you wouldn't have the psi increase.
    Dave S.
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    Re: Old filter sand - up close!

    That is incredibly cool.
    TFP Moderator Chris V. ~16K Pool & Spa, 48NSF DE, IG Plaster Circa 2000, Intermatic PE653, Challenger pump with a 2 speed B2984, 20gal stenner chlorine injection, Houston, TX
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    Re: Old filter sand - up close!

    Quote Originally Posted by duraleigh View Post
    We never suggest changing the sand. It comes to you millions of years old already so 20 years in a pool has little affect.That simply means your sand is catching particles and the particles are adding resistance to your system.

    Posting a complete set of test results is the first step but your water is not perfectly clear or you wouldn't have the psi increase.
    I suppose it could be catching the plaster "dust" that was created after the acid wash. I've noticed I can brush the bottom and a bunch of "dust" will get kicked up. My new robot has filters that catch it and I rinse out a bunch of what looks like sand from its filters after every use.

    Tests from last night are:

    FC: 4
    CC: <.5
    PH: 7.6
    TA: 80
    CH: 275
    CYA: 15-ish?

    I've just added more CYA a few days ago so I'm still waiting on it to register properly. I'm out of reagent for the test though... just waiting for it to get here...
    22,000 gallon in-ground kidney-ish shape: 1 HP pump and Triton TR60 sand filter. NEW: Dolphin Nautilus robot! :)

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    Re: Old filter sand - up close!

    Yes, plaster dust could well account for the fairly rapid pressure rise.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Old filter sand - up close!

    Quote Originally Posted by JasonLion View Post
    Yes, plaster dust could well account for the fairly rapid pressure rise.
    I guess now that I think about it, that makes sense...

    Any tricks for dealing with it?
    22,000 gallon in-ground kidney-ish shape: 1 HP pump and Triton TR60 sand filter. NEW: Dolphin Nautilus robot! :)

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    Re: Old filter sand - up close!

    Not really. The dust shouldn't last all that long. Brushing regularly will help clear it up more quickly. While it does last, you just need to backwash more frequently.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Old filter sand - up close!

    New sand looks a lot like old sand

    Think of sand grains like tiny river rocks...they've been beat to heck for a very long time getting from wherever they came from to wherever they were deposited while getting carried down a mountain then a stream and then a river.

    "New" sand:
    25000 gal in ground plaster. '79 vintage. Cartridge filter.

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    Re: Old filter sand - up close!

    Quote Originally Posted by freqz View Post
    New sand looks a lot like old sand

    Think of sand grains like tiny river rocks...they've been beat to heck for a very long time getting from wherever they came from to wherever they were deposited while getting carried down a mountain then a stream and then a river.

    "New" sand:

    I guess I was thinking new sand would look more like this "Lumber Yard" sand:



    Or this sand from Guam:





    But... neither of those are pool grade silica sand.
    22,000 gallon in-ground kidney-ish shape: 1 HP pump and Triton TR60 sand filter. NEW: Dolphin Nautilus robot! :)

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    Re: Old filter sand - up close!

    The pool grade sand will be a lot closer to frac sand which will typically be pretty 'round'.
    25000 gal in ground plaster. '79 vintage. Cartridge filter.

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    Re: Old filter sand - up close!

    I gotta say, this is a cool thread. It really does support the standing theory that pool sand doesn't "go bad".
    IG gunite/plaster pool/spa Started 1/17/14, Plastered 5/16/14
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    Re: Old filter sand - up close!

    Thanks for posting..........very interesting. Kinda backs up our suggestion of not needing to "change" the filter sand.
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    Re: Old filter sand - up close!

    Quote Originally Posted by freqz View Post
    The pool grade sand will be a lot closer to frac sand which will typically be pretty 'round'.
    Where does the pool sand come from? Why is it round?

    - - - Updated - - -

    Quote Originally Posted by woodyp View Post
    Thanks for posting..........very interesting. Kinda backs up our suggestion of not needing to "change" the filter sand.
    If I can get my hands on some new filter sand, we can really compare!
    22,000 gallon in-ground kidney-ish shape: 1 HP pump and Triton TR60 sand filter. NEW: Dolphin Nautilus robot! :)

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    Re: Old filter sand - up close!

    Quote Originally Posted by chjade84 View Post
    Where does the pool sand come from? Why is it round?

    - - - Updated - - -



    If I can get my hands on some new filter sand, we can really compare!
    Want me to mail you an envelope full? :P I have bags of it stacked, ready to go into my filter.
    IG gunite/plaster pool/spa Started 1/17/14, Plastered 5/16/14
    Size: 12'-21'x39' free form, depth ranging from 4' to 7, attached 6 person spa with spillover.
    Equipment: Whisperflo 2hp pump, Pentair 30" sand filter, Pentair Mastertemp 400k BTU heater, 1hp Whisperflo for waterfalls, and a blower for spa floor

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    Re: Old filter sand - up close!

    Quote Originally Posted by chjade84 View Post
    Where does the pool sand come from? Why is it round?

    - - - Updated - - -



    If I can get my hands on some new filter sand, we can really compare!
    Same way a river rock is round...
    25000 gal in ground plaster. '79 vintage. Cartridge filter.

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    Re: Old filter sand - up close!

    Quote Originally Posted by mrcarcrazy View Post
    Want me to mail you an envelope full? :P I have bags of it stacked, ready to go into my filter.
    Haha surely I can find some around here. Can you imagine what the post office would think about that? Just a letter envelope with a tablespoon of sand in it and nothing else? lol

    Quote Originally Posted by freqz View Post
    Same way a river rock is round...
    Well sure, but I guess I meant why is this silica sand round while other sands are jagged? Is it more a property of silica or a property of where it is found vs. "normal" sand?
    22,000 gallon in-ground kidney-ish shape: 1 HP pump and Triton TR60 sand filter. NEW: Dolphin Nautilus robot! :)

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    Re: Old filter sand - up close!

    EDIT:

    I didn't think as many people would find this as interesting as I did!

    So, I took photos with the DSLR instead of the cheap scope camera so you can see the grains in more detail.
    22,000 gallon in-ground kidney-ish shape: 1 HP pump and Triton TR60 sand filter. NEW: Dolphin Nautilus robot! :)

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    Re: Old filter sand - up close!

    Quote Originally Posted by chjade84 View Post
    Haha surely I can find some around here. Can you imagine what the post office would think about that? Just a letter envelope with a tablespoon of sand in it and nothing else? lol



    Well sure, but I guess I meant why is this silica sand round while other sands are jagged? Is it more a property of silica or a property of where it is found vs. "normal" sand?
    It all depends on how long/how far it took to get from where it came from to where somebody dug it up. Some application you want more angular sand, for some you rounder sand. Filtering is one of those instances where you'd prefer the rounder variety. (angular pieces fit together in weird ways and could make your filter either too permeable or not permeable enough)
    25000 gal in ground plaster. '79 vintage. Cartridge filter.

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