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Thread: concrete pool ground water issue ?

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    concrete pool ground water issue ?

    I just bought a new house with a 9 foot hybird pool I would say about 20 years old. the side walls are fiberglass and the bottom bowl is concrete, i am in the process of trying to drain the pool since it need to be repainted, I know this is not a fix but a re plaster job is out of the question this year. The pool sits in a very low point in the yard and once i get to about 4 foot of water left in the pool the hydrostatic valve opens up and lets the ground water back in (I know its doing what its designed to do ) the problem i am having is getting the ground water out from under the pool. By my pool pump there is a 1.5in PVC pipe that not connected to the pump in any way. I tested this line and it looks like it goes under the pool shell to remove ground water. I Have an old pool pump 1.5 hp that I connected to this line to try and remove the ground water but i cant keep the pump primed long enough to created enough suction to get the ground water up to the pump (about 6 feet vertical rise) If anyone had any tips or know what to do in this situation please let me know
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    cowboycasey's Avatar
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    Re: concrete pool ground water issue ?

    That is very good that valve is in there.. You will need a sump pump or garbage pump down in the bottom to pump out the water, you can get them from harbor freight and other places. Here is a 1/4hp pump from them.. 1/4 HP Submersible Sump Pump with Vertical Float 2800 GPH
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    Re: concrete pool ground water issue ?

    thanks for the reply, I have a sump pump seen at the top on the picture 1hp 2640 GPH from harbor freight I used it to pump the water out of the pool but the problem with using this method is i have to have to keep the bottom dry for the paint to stick, this pump will only get it down to about 2 inches before it looses prime and it will take about 5 inches of water to prime back again ?

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    Re: concrete pool ground water issue ?

    A sump pump won't solve your problems. Call a septic tank service and see if they can help by hooking up to the 1.5 inch line. That is small for a dry well and I would expect more than just one. But you have the right idea pump out the water surrounding the pool, empty the pool then paint. Do not plug the hydro static valve.
    22k gallon IG pebblefina, Jandy 1.5 HP VS, Jandy CV Cartridge filter, Fafco solar panels, Polaris 360 supply side cleaner, waterfall

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    JoyfulNoise's Avatar
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    Re: concrete pool ground water issue ?

    I think it all depends on where that 1-1/2" PVC line bottoms-out at. If it was designed to only pull water away from the fiberglass sidewalls, then you will never be able to drain all the water from under the concrete shell.

    Do you have any idea about the ground water in your area? How high it usually goes? Any neighbors to ask?

    It might be the case that the only way to drain the water from under the pool is to leave the hydrostatic valve open and to keep pumping out the water until it finally subsides. There may be times of the year, due to prevailing weather conditions, that the ground is mostly dry and times when it is saturated with water. If there's a lot of ground water where you pool is, then you may never be able to fully drain from under the pool. It's all speculative and trial and error until you get some solid information on the ground water conditions for your area.
    Matt
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    Casey's Avatar
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    Re: concrete pool ground water issue ?

    Can you add your state to your profile please. You may have to wait til the ground dries up some too.
    I'd bet you my bikini you'll never get TFP water from a pool store!

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    Re: concrete pool ground water issue ?

    It looks like you have soil behind the rocks near the deep end ladder. You could bore a hole there deeper than the pool, take an 8" Diameter PVC pipe and place it in the hole. Then drop a submersible pump down the pipe. When finished, a skimmer lid on top of pipe.
    Check utilities before dig of course.
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    Re: concrete pool ground water issue ?

    I am at the lowest spot in the neighborhood and all the neighbors yards drain toward the pool I have the Hydrostatic valve propped open right now so I can tell where the ground water is at , it looks to be about 4 feet. it looks to be that i will have to wait till the rain stops for a while , i live in Tennessee so that going to be a while

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    Casey's Avatar
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    Re: concrete pool ground water issue ?

    Quote Originally Posted by banditig View Post
    It looks like you have soil behind the rocks near the deep end ladder. You could bore a hole there deeper than the pool, take an 8" Diameter PVC pipe and place it in the hole. Then drop a submersible pump down the pipe. When finished, a skimmer lid on top of pipe.
    Check utilities before dig of course.
    This is correct n it's called a well point. You can search it using the search button.
    I'd bet you my bikini you'll never get TFP water from a pool store!

    24' Sharkline Venture De Filter

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    Re: concrete pool ground water issue ?

    I got the pool finally painted, we where not able to get the water down all the way maybe a couple of inches (hints the white spot in the bottom) we had to put the sump pump on a timer to keep it from burning up 5min off and 1 min on to keep the water at that level. the ground water was still to high i was scared to plug up the hydro valve. Also shown in the pic I did find the right glue/epoxy to lay the tile on the plastic track (corning 799 clear) so far it seem to work well. So now that all the hard work is done and the pool is full I have one more question for ya.

    pool - Album on Imgur

    I got my test kit in the taylor 2006 and the results are
    FC = 4
    CC = 0
    PH = 7.2
    TA = 70
    CH = 100
    CYA = 0 to 20 (I could see the black dot still with the tube filled )

    I know from reading here that my CH should be 250 to 350 for a concrete pool , but since this pool is only half concrete should that number change to like 200 ?
    20K hybird inground pool (fiberglass walls with concrete bottom) Hayward 1.5hp super pump Hayward sand filter S210T, Taylor K2006 test kit

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    Re: concrete pool ground water issue ?

    Quote Originally Posted by laganm21 View Post
    I just bought a new house with a 9 foot hybird pool I would say about 20 years old. the side walls are fiberglass and the bottom bowl is concrete, i am in the process of trying to drain the pool since it need to be repainted, I know this is not a fix but a re plaster job is out of the question this year. The pool sits in a very low point in the yard and once i get to about 4 foot of water left in the pool the hydrostatic valve opens up and lets the ground water back in (I know its doing what its designed to do ) the problem i am having is getting the ground water out from under the pool. By my pool pump there is a 1.5in PVC pipe that not connected to the pump in any way. I tested this line and it looks like it goes under the pool shell to remove ground water. I Have an old pool pump 1.5 hp that I connected to this line to try and remove the ground water but i cant keep the pump primed long enough to created enough suction to get the ground water up to the pump (about 6 feet vertical rise) If anyone had any tips or know what to do in this situation please let me know
    I have the exact same pool construction. Mine was built in 1973, so yours might be a tad older than 20. And mine is definitely bigger than 20K gallons.
    Geebot
    Chicago, IL
    30K gal, InGround Plaster Finish, 3.5'-9.5', Maytronics S300 Cleaner

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    Re: concrete pool ground water issue ?

    Quote Originally Posted by Geebot View Post
    I have the exact same pool construction. Mine was built in 1973, so yours might be a tad older than 20. And mine is definitely bigger than 20K gallons.
    I am just guessing at the gallons of the pool, When i filled it up it took 36 hours And i basing that off of every 9 hours the standard garden hoes will produce 5 thousand gallons (well that what i read somewhere
    20K hybird inground pool (fiberglass walls with concrete bottom) Hayward 1.5hp super pump Hayward sand filter S210T, Taylor K2006 test kit

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    Re: concrete pool ground water issue ?

    Draining ground water can be a huge thing if there's a lot of it. It's best if you can drain it off without having to pump it, as that gets costly in the long run. On the other hand it gets expensive to have the water there as well, if you're heating your pool lot of the heat will be drained away by the ground water.
    Indoor pool appr. 27'x13'x5', rectangular, concrete pool with epoxi coating, Sand filter with 1.5 hp pump, Electric heater + heat pump, Automatic system for chlorine and acid
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