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Thread: Draining a pool to reduce salt

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    Draining a pool to reduce salt

    I accidentally added too much salt to my pool. (I added, and my Jandy kept misreporting the correct salt amount, over the course of a couple of weeks, until it was too late and now I know.) So...I'm going to have to drain it, at least partially, right?

    Any recommendations on how best to do this? Does salt typically settle to the bottom, in other words, if I drain from the bottom, am I best off draining before the pump begins running in the morning, so that the majority of the salt is sitting at the bottom and that's what gets washed out?

    My salt cell has been very temperamental and might have reached the end of its life. Is there any harm in not draining the pool, leaving the SWG at 0% chlorine production, and just having a traditional chlorine pool for the year, and revisit this next year?

    I have a 15k gallon pool and the salt concentration, as best I can tell, the salt reading is somewhere around 6000. The calculator is telling me, to get it down to 3000, I'll have to dump 50% of my water. How accurate is that calculation? How can I do this in the most intelligent way? If I really have to replace 50% of my water, it will cost me about $1500 (!!) in a water bill.

    My city requires a $28 permit for any quantity of pool draining, plus I'm in California so am very conscious of the water shortage and would like to really figure this out as best as I can, so I don't make any more mistakes.

    Any advice?
    Los Angeles (San Fernando Valley)
    15k gallon in-ground (IG) pool (I believe it's plaster)
    DE filter (Heyward), using cellulose instead of DE
    Jandy APURE1400 3-port salt cell

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    Divin Dave's Avatar
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    Re: Draining a pool to reduce salt

    Hi ddas,

    sorry to hear about your high salt woes. The only way to remedy it is to get rid of some of the salt water. And yes, about 50% is correct.

    It doesnt evaporate out with water.
    And as long as there is enough water in the pool, it will stay dissolved. It doesnt sink or concentrate at the bottom.

    Scenario 1 - is as you mention, empty half all at once.

    Scenario 2 - would be to drain a little bit over a long period of time. Perhaps a year and you could maintian your FC with chlorine. If you have to backwash, that could certainly help in the process.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
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    Re: Draining a pool to reduce salt

    I'd be inclined to check the operating perams of a new cell, at $1500 for water I wouldn't be draining anytime soon, adding manual chlorine will probably cost you something in the region of a new cell anyway, plus the PITA of it. MY cell runs fine at 5000 probably more. over the course of a season the salt will come down 1-2000 ppm with backwash/splash/rain/refill. I have lost 750ppm in 2 months here.
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    Mod Squad pooldv's Avatar
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    Re: Draining a pool to reduce salt

    My pentair IC40 doesn't seem to mind high salt either. I had the same issue a couple of years ago with low salt error and me adding salt like a madman. After quite a few extra bags of salt I read up on TFP that swcg do not work in cold water and return low salt error. My pool went from not tasting salty to tasting pretty darn salty. I never tested it because as soon as it warmed up it started making chlorine again. I haven't had to add salt for over two years!
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    Mod Squad jblizzle's Avatar
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    Re: Draining a pool to reduce salt

    You may want to re-check your cost estimates as that would be a record (by a long shot) if it was true. Unless you are having it trucked in or have fines associated with it. Expensive municipal water is around $10/1000 gallons ... which would make your costs around $80. Replacing that amount in my pool would cost me less than $10 (although mine is pretty cheap).
    Jason, TFP Moderator
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    Re: Draining a pool to reduce salt

    Thanks a lot for the replies. It's really, really appreciated.

    Regarding the water math, I'd love to know if I misheard. The lady in the water dept. on the phone told me it would be $1.78 per cubic foot of water (roughly = 7.5 gallons). So half my pool is 7500 gallons. Divide that by 7.5 gallons, and that gives me 1000 cubic feet. Multiply that by $1.78 and it's $1780.

    To double-heck, I just looked it up on the web site and I don't know how to read this but it says: http://imgur.com/Ak82JfB -- please do let me know if I made a calculation error.

    I kind of like Divin Dave's idea of draining a little bit over time. What if I backwashed my filter once a month (or whatever), replacing the lost water as necessary, and over the course of 12 months, hopefully I get my salt back to a normal level? That way I can hopefully keep my water usage in the cheaper range (as you can see in the above link, the water company charges more as you use more), as well as avoid having to get the permit.

    My SWG is definitely giving me errors about the salt being too high. (I've since cleaned its sensor and now its reading agrees with my pool store's salt testing kit.)

    I really don't mind turning the SWG to 0% for several months or the entire year, and then manually supplementing the pool with liquid chlorine. Liquid chlorine isn't expensive, I keep some on hand anyway, and I test my pool regularly, so I can keep it within range manually. No big deal at all. My only concern would be if there is any danger to the equipment, the salt cell, or anything else. Just so I'm clear, there really isn't a "process" of converting a salt pool to a regular chlorine pool, is there? If I understand it right, it's as simple as: if the SWG is off (or malfunctioning), then you have to add chlorine manually to keep the FC within recommended levels. So there's not really any harm in me giving the SWG a break for a bunch of months until the salt comes back in range?

    Any further thoughts on what you guys would do given the situation?
    Los Angeles (San Fernando Valley)
    15k gallon in-ground (IG) pool (I believe it's plaster)
    DE filter (Heyward), using cellulose instead of DE
    Jandy APURE1400 3-port salt cell

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    Divin Dave's Avatar
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    Re: Draining a pool to reduce salt

    There is no converson process from SWG to liquid chlorine. Just turn it to 0 and add liquid chlorine and you're good to go. It wont damage anything.

    In the image you posted, it looks to me like the cost is 1.78 per 100 Cubic Feet. (not 1 cubic ft).

    So, 1000/100*1.78= 17.80$

    I looks like there is also a Water Cost Adjustement of 1.74 per 100 cf
    17.40$

    I am guessing this WCA is added to the water charge.

    17.40+17.80= 35.20 plus whatever taxes they will add on.
    In lots of places, additional sewer and garbage is added to each 1000 gallons of water. So that might increase the cost too.

    If I were you, I would call the lady at the water company back and reconfirm what that link says.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
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    Re: Draining a pool to reduce salt

    When I filled my approx 12K pool at the old house, it was 120 dollars added to the water bill, I can't imagine it would be so much. Whatever you do, i would not do partial drains and refills as it will take much much more than just doing it once. If you aren't allowed to drain, you could just fill it to the top and let water flow out when it rains assuming your drains and such are good. I forgot about my pool when I was adding some water and ended up needing to add some salt because of it.
    8000 gal diamond brite pool with 650 gal spillover spa, Pentair 3hp VS pump. Jandy Cartridge filter and Jandy Heat Pump. Jandy PDA automation system with 2 Pentair Laminars. SmartPool NC74S Robotic Pool Cleaner.

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    JasonLion's Avatar
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    Re: Draining a pool to reduce salt

    Looking at the water company web site I see roughly $3.50 per 100 cubic feet, which agrees with what Dave calculated. To replace 7500 gallons that comes to roughly $35.

    When replacing water, you only need to bring the salt level to below the upper limit of your SWG. You can go down to the recommended level from there more slowly as you get rain and/or backwash the filter. The max salt level for that SWG is roughly 4000, so that is more like a 33% water replacement. I would replace a little more just to be sure, but certainly less than 40% replacement.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Draining a pool to reduce salt

    My cost to fill a 16,500 gallon pool in Long Beach was $80. I would be very surprised if water was 20X that anywhere in California.

    Right now there might be some restrictions, but I would start replacing water an inch or two at a time to reduce the salt content to around 4000ppm. That way you should avoid the permit fee and your water usage doesn't take a one time hit. The Jandy SWG should work between 2500-4000ppm.
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    Mod Squad YippeeSkippy's Avatar
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    Re: Draining a pool to reduce salt

    Have you tested the salt level of the pool's water yourself (salt test kits are available from TFTestkits.com) to confirm what your cell says? I don't trust my cell to be accurate because my testing says otherwise and yet it chugs along perfectly happy even though it thinks my salt level is higher than it really is.
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    Re: Draining a pool to reduce salt

    OK, thanks again everybody. Ping, I think you nailed it. I'm really glad I did my math wrong. And because of the tiered water rates, I much prefer doing this a little at a time. Fortunately, my pool equipment is in a secluded, non-public corner of the yard where there is no grass/vegetation. So to drain a few inches on a day and instantly refill it is probably doable. Thanks to your advice, I think I'll do that: take the long road on this. Small quantities of regular draining and refilling and hopefully I'll get this problem licked over time.

    I'll also look at getting the salt test kit. I noticed it's $24 on TFTK but $14 at Amazon (sorry Amazon haters... ) Right now, my pool store (who have run the test using a couple different methods) and my Jandy are reporting similar numbers (low 6's), and the Jandy is giving me regular error codes that the salt is too high, so there's definitely a problem. But all my numbers, including that my pool is 15k gallons, are rough estimates (it's an odd bean-shaped pool) so I'm much more content to take a gradual approach until all indicators agree things are back within range.

    I'm really grateful for the experienced and generous people on this forum. I'll report back when I have something concrete to report.
    Los Angeles (San Fernando Valley)
    15k gallon in-ground (IG) pool (I believe it's plaster)
    DE filter (Heyward), using cellulose instead of DE
    Jandy APURE1400 3-port salt cell

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    Re: Draining a pool to reduce salt

    I would trust the pool store results for the salt reading and the SWG has it reading high. None of the salt test kits, that most of us get, are extremely accurate but are accurate enough between the SWG reading and an occasional test done with test strips or the Taylor test kit. What truly matters is what the SWG is reporting, but whenever it reports low I always double check it with a test before adjusting the water with more salt.
    16k gal plaster with raised spa, Jandy DEV60 filter, 2 HP 2-speed SHPF Jandy Stealth pump
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    Re: Draining a pool to reduce salt

    I just thought of one downside -- correct me if I'm wrong -- if I backwash the filter daily (or whatever), I'm going to have to re-add DE or cellulose after every backwash aren't I? Hmmmm. That is an extra step and extra time. Not a deal breaker, but just thinking aloud that it might not be as convenient as I anticipated it being.

    I assume it's not good to let my pool be without DE/cellulose for more than a day or two...
    Los Angeles (San Fernando Valley)
    15k gallon in-ground (IG) pool (I believe it's plaster)
    DE filter (Heyward), using cellulose instead of DE
    Jandy APURE1400 3-port salt cell

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    JasonLion's Avatar
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    Re: Draining a pool to reduce salt

    With a DE filter, it is not good to run the filter without DE (or cellulose) for more than a few minutes.

    Also, I'm not sure why you would be talking about backwashing the filter every day. The only time that should come up is when cleaning up an algae outbreak.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    pwrstrk's Avatar
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    Draining a pool to reduce salt

    You only want to back wash when the filter pressure rises 25% above what the clean pressure is.
    Jeff
    24'x54" AG Morada RTR (by wilbar) 13'500 gal. Hayward Powerflo Matrix 1hp 2 speed. Hayward Perflex EC65 DE filter.

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    Re: Draining a pool to reduce salt

    I thought the only [easy] way to drain my pool was to backwash the filter. Is there another way that doesn't involve doing that? (For reference, here's a quick photo/diagram of my pool equipment, as I'm still feeling pretty new at this: http://imgur.com/DBDGd6d)
    Los Angeles (San Fernando Valley)
    15k gallon in-ground (IG) pool (I believe it's plaster)
    DE filter (Heyward), using cellulose instead of DE
    Jandy APURE1400 3-port salt cell

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    Mod Squad jblizzle's Avatar
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    Re: Draining a pool to reduce salt

    You do not have a multi-valve on your filter, only a push/pull backwash valve. So the only way to remove water with the pool pump would be backwashing (you do not have the waste option); however, it is not recommended to remove a lot of water in this manner as it could damage the grids and cause dirt to build up inside them.

    The easiest and fastest way is to rent or buy a submersible pump.

    Or if you have a hill available, you could siphon the water out with a hose.
    Jason, TFP Moderator
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    JasonLion's Avatar
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    Re: Draining a pool to reduce salt

    Another option, possibly more work, possibly less, would be to remove the top of the filter and run the pump that way to drain. Nearly all of the water will then come out of the filter, rather than go back to the pool. It can be a little messy, but is safer for the filter and doesn't require any additional equipment.

    A variation on this approach is to remove the drain plug. With some creativity you could even make an adapter from the drain pug socket to a hose. More water will go back to the pool this way, but you will still drain at a useful rate.

    Both of these will let DE out of the filter along with the water, increasing the "mess" a bit. So they aren't really ideal.

    Some people prefer to plumb in a drain connection, or switch to a rotary multi-position main valve, to avoid this kind of issue.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  20. Back To Top    #20

    Re: Draining a pool to reduce salt

    Quick question -- hoping you guys are still with me on this thread -- JasonLion, is that technique safe? As in:

    1) I open the drain plug on the filter, empty the filter.
    2) I open the filter itself, remove the grids (they need rinsing anyway -- my pressure is +10 higher than when clean).
    3) While the filter is open (the top is off), I switch the pump on -- causing the pump to suck water out of the pool, bringing it into the filter, but the filter is half open, so it's going to spill, which is what I want. I can spill as much water as my pool equipment area can take without flooding.

    Is that safe? I won't break/damage anything?

    I thought the pump was only supposed to be used when the system is entirely closed, so it doesn't suck air.
    Los Angeles (San Fernando Valley)
    15k gallon in-ground (IG) pool (I believe it's plaster)
    DE filter (Heyward), using cellulose instead of DE
    Jandy APURE1400 3-port salt cell

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