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Thread: How to Drain IG Pool?

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    How to Drain IG Pool?

    New owner of an old pool (previously maintained by a pool service!!):

    FC = 1
    pH=7.2
    Alk=110
    Hard=3900
    CYA = <100

    I know I need to drain my IG pool to get the CYA down to acceptable levels, but exactly how do I do that? I can backwash, but it seems to stop draining at the top of the first step (Water flow drops significantly, skimmer makes strange sounds, pump seems to be straining) According to the calculator, I need to drain about 60-70% of the water. Oh, and make the directions as simple as possible for mechanically-challenged TIA
    20k, IG plaster, 1.5HP Pentair Challenger, DE filter,

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    linen's Avatar
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    Re: How to Drain IG Pool?

    Welcome to tfp, elissyf

    How did you get your test numbers? Be careful if the cya number is from a pool store...they get this one wrong more than right. If those numbers are from test strips then I would not trust them at all. Either way, before you go and drain, it would be best to get a reliable cya measurement. My first recommendation would be to get your own test kit. See: http://www.troublefreepool.com/pool-...kit_comparison

    Did you mean your cya is more than or less than 100? If less, by how much?

    I highly doubt your CH is 3900, that would be the highest I have ever seen. This would also be a good reason to get and appropriate test kit.

    As for the draining, like I said above, I would wait to drain until you have good numbers for cya and CH.

    With that said, do you have a floor drain?
    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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    elwood58's Avatar
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    Re: How to Drain IG Pool?

    Follow the advice on getting your own test results before proceeding. Once you determine the need for a large water replacement, you can then decide whether to drain using your pool pump, or rent a submersible pump.

    Your flow is slowing when the water gets below the skimmer and any of its balance lines, and starts sucking air. It sounds like your main drain is plumbed through your skimmer. If not, you need to set the valves to pull 100% from the main drain.
    19204 Gallon L Shape with a 10X10 2nd Step Baja Ledge. Intellichlor IC-40, IntellipH, Cartridge Filter, Pentair Heater/Chiller (Heat Pump). Tons of Deck with Deck Jets. Construction Complete 6/5/17.

    "If you don't measure it, you can't manage it!"

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    Isaac-1's Avatar
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    Re: How to Drain IG Pool?

    Once you are sure you need to drain, if your main pump can't do it, a cheap submersible sump pump connected to a garden hose will work (cheapest ones I have seen are at Harbor Freight for about $30-$50 depend on sales), you don't need any fancy features like automatic cut off float switches, etc, just plug it in and let it run until the water is low enough this may take a day or more depending on the size of the pump and your pool. Just be aware if your in an area with a high water table that it is possible for pools to float out of the ground when drained.

    Ike
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
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    Re: How to Drain IG Pool?

    Agree with the above posters, but I will give you a little background. I just drained about 80% of my water yesterday and will drain the remaining today. There are a couple of concerns with draining a pool.

    For a plaster pool the main concern is having it pop out of the ground due to hydrostatic pressure. This is a result of the ground water being higher than the bottom of the pool (generic classification).

    In my case I could not find anyone to tell me how high the ground water (water table) is in my area. Based on recommendations from others on this site I bought a post hole digger ($26) from Home Depot and dug a hole about 5' deep and let it sit for a day. After a day i checked it and there was no water present so i feel confident that my water table is lower than my pool. (5')

    For a fiberglass pool there are two main concerns, one is the same as above and the second is that the walls will possibly collapse in as you drain water from the pool. However if the pool was built correctly this should not be an issue. The post I have seen in regards to draining a fiberglass pool were to drain no more than 25%, refill and repeat until CYA and CH are within acceptable levels.

    In regards to the draining process I set my filter to waste and isolated the pump to pull from the main floor drains and let it run. If you do not have floor drains or if you do not believe you pump can handle the extra stress you can rent a pump with 100' of hose from Home Depot for $60. You place this pump directly into the pool and run the hose (like a firemans hose) out to where you want to drain the water.

    You do not want to drain the water to an area where it will go into the ground and possibly find its way to your pool as this will greatly raise the water table temporarly.

    I will also be doing an acid wash this weekend and can provide feedback later if you are interested.
    25,000 gallon in ground white plaster- 1 1/2 HP Pentair SuperFlo pump - 60 sqft FNS DE filter (with FiberClear), 1999 Sundance Optima 850 hot tub.
    Manassas Park, VA

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    Re: How to Drain IG Pool?

    Thanks for the answers. I did mistype the Hard = 390, NOT 3900. I used the Taylor kit to test so I feel pretty good about my results (aside from typos...) I will do the cya test and find the exact reading.

    I will take another look at the valves to see if I can switch from the skimmer drain to the main drain. Its an older 1980 pool so I'm wondering if they routainly plumbed the main drain thru the skimmer?
    20k, IG plaster, 1.5HP Pentair Challenger, DE filter,

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    Mod Squad jblizzle's Avatar
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    Re: How to Drain IG Pool?

    My 70s pool has the floor through the skimmer ... so did my 2000s pool. Pretty common.
    Jason, TFP Moderator
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    Isaac-1's Avatar
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    Re: How to Drain IG Pool?

    During the late 1970's through 1980's it was common to plumb the main drain through the skimmer as an anti entrapment measure, older pools from the 1950's and 1960's often had drains that could potentially entrap swimmers , a simple solution to this problem was to run the line from the main drain to the bottom of the skimmer, if someone were to get sucked into the main drain, the vacuum could be broken by the additional flow from the skimmer potentially allowing the pump to suck air and loose prime. A side effect of this design is of course that any time the water level drops down to around the skimmer level the pump starts sucking air.

    Ike

    p.s. note my pool built in 1980 only has a skimmer, no main drain.
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
    I use and endorse TFtestKits TF-100 from http://tftestkits.net
    ~Remember TFP counts on your donations to keep this site ad free~

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