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Thread: Winterizing Concrete Pool - how much water can i drain without risking heaving?

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    Winterizing Concrete Pool - how much water can i drain without risking heaving?

    I'm a first timer with some questions about winterizing (I have read the recommended threads).

    First, in order to lower my water below my equalizer line, my water is down to the top of the first step in the shallow end of my pool. I'm worried that if i close it with the water this low, the ground could heave and cause a crack in my concrete. Does anyone know how much water I have to keep in the pool in order to avoid this?

    Second, I've attached a rough drawing of my system. Do I blow out all of the lines with my shop vac from the skimmer? Or something else? Then, after I've blown out the lines do i then let the water out of the heater and filter through their plugs? How will I know if i have gotten all the water out?

    Third, do I use anti-freeze? If so, how much and where do i put it in? As my drawing shows, my equipment is on several levels (above grade, at grade, below grade). Obviously, I can't put the antifreeze in the vertical lines unless I fill all of the piping. Should I do this??? It seems like a ton of antifreeze would be needed!

    Thanks for your help.
    Pool: In-ground; 18,500 gallons; painted concrete (I think -- it was built in the 1940s); Triton II Sand Filter, pre-1991; Hayward Super Pump II; Pentair heater

    Spa (separate): in-ground; cartridge filter, 3 Hayward Super Pump IIs (1 for circulation, 2 for jets);Pentair heater

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    Re: Winterizing Concrete Pool - how much water can i drain without risking heaving?

    Lowering the water below your returns should have no affect on your cement, I believe it would only be about 30% of your water going out. Leaving roughly 14,000 gallons still in there for weight. I gallon of water weighs 8.5 lbs, that's 110,000 lbs pushing down on your pool bottom. If you are in an area that has a very high water table and you are concerned with this, then you should get a skimmer plug and Anderson duck plugs. This way you about 200 gallons out of pool only.

    I would blow all lines from the equipment pad, set multiport on filter to waste, disconnect the pump and blow in that connection there, it will also remove the water in your filter. As you get each line blown free of water, you can go around the pool and plug in sequence. This ensures the air has one last final route to push out any left in water. If you do drain below the returns, you can then add antifreeze in that same line and once mist is showing from all returns, you can then do short bursts on air to get antifreeze to the lowest part of your lines. If you have a main drain and its plumbed to the bottom of skimmer, buy some foam rope and push about 4' inside that line, then plug it. Your size pool should require no more then 4 gallons of antifreeze.
    I know its scary, but its actually quite easy, just tedious work. If you are doing this yourself every season, I highly recommend a Cyclone Pool Blower. It will pay for itself in terms of confidence that all water has been removed.

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    Re: Winterizing Concrete Pool - how much water can i drain without risking heaving?

    Thanks for getting back to me so quickly. I'm nervous and I've put it off too long trying to make sure I'm doing it right! My problem is that once I drain below the equalizer, which is about 18" to 2 feet below the bottom of my skimmer, I've gotten rid of almost half of the water. In the shallow end, only one of my four steps is covered with water and I'm below my two returns by about two feet (only about 6-8 inches left at shallow end). I think this means I have about 9000 gallons left. I'm not aware that the water table is high here (how would I know this?) and the pool is on a hill. Am I still ok?

    As regards blowing things out: I have only three valves, two at the pump and one at the multiport, so there's not much I can close off. All the stuff in the pool hut is well below grade, so I'm wondering if I should blow from the returns and push the water to the drains below grade. At least I'd be working with gravity. There are drains in the pool hut.

    I know the pool guys who used to do this used rubber plugs in the skimmer -- one for the equalizer and one for the line to the pump. Should I be using rubber plugs for all of the openings?

    In the skimmer, it looks like the equalizer line is pretty empty. I blew a little air into it and very little came out. Am I right in assuming that I need to close off the equalizer before I blow out the other line in the skimmer? Otherwise it seems like the water in the second line is going nowhere. I don't have a main drain, only the equalizer.

    Why does the pool blower make a difference? Is it stronger than a shop vac?

    It's raining and cold today, so I didn't get much chance to try much here. I'll give it another shot tomorrow. I appreciate your help.
    Pool: In-ground; 18,500 gallons; painted concrete (I think -- it was built in the 1940s); Triton II Sand Filter, pre-1991; Hayward Super Pump II; Pentair heater

    Spa (separate): in-ground; cartridge filter, 3 Hayward Super Pump IIs (1 for circulation, 2 for jets);Pentair heater

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    Re: Winterizing Concrete Pool - how much water can i drain without risking heaving?

    Quote Originally Posted by neutral0 View Post
    Thanks for getting back to me so quickly. I'm nervous and I've put it off too long trying to make sure I'm doing it right! My problem is that once I drain below the equalizer, which is about 18" to 2 feet below the bottom of my skimmer, I've gotten rid of almost half of the water. In the shallow end, only one of my four steps is covered with water and I'm below my two returns by about two feet (only about 6-8 inches left at shallow end). I think this means I have about 9000 gallons left. I'm not aware that the water table is high here (how would I know this?) and the pool is on a hill. Am I still ok? If you are on a hill, its very unlikely you have a high water table, that goes in your favour, its water that actually lifts a pool out of the ground when its force is greater then the force of the unfilled pool.

    As regards blowing things out: I have only three valves, two at the pump and one at the multiport, so there's not much I can close off. All the stuff in the pool hut is well below grade, so I'm wondering if I should blow from the returns and push the water to the drains below grade. At least I'd be working with gravity. There are drains in the pool hut.You certainly can do it this way, just ensure you have a good air flow and make sure you see mist for at least 3 mins
    I know the pool guys who used to do this used rubber plugs in the skimmer -- one for the equalizer and one for the line to the pump. Should I be using rubber plugs for all of the openings? It certainly ensures that no water can get back into the pipes, a standard plug with Teflon will work as well.

    In the skimmer, it looks like the equalizer line is pretty empty. I blew a little air into it and very little came out. Am I right in assuming that I need to close off the equalizer before I blow out the other line in the skimmer? Yes you shouldOtherwise it seems like the water in the second line is going nowhere. I don't have a main drain, only the equalizer.

    Why does the pool blower make a difference? Is it stronger than a shop vac? Shop vacs will blow water fine, they will rarely empty a main drain line, but you don't have one so you are fine with shop vac. I used to just duct tape mine to whatever pipe I could, then I would walk around and work to close each lines.

    It's raining and cold today, so I didn't get much chance to try much here. I'll give it another shot tomorrow. I appreciate your help.
    Hope this helps

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    Re: Winterizing Concrete Pool - how much water can i drain without risking heaving?

    Yesterday, I drained the pool to below the equalizer line. Before it reached that point, I opened up the drains in all the lines that were below grade in the pool hut. I thought this might drain the pool altogether to about the line of the equalizer, since it is all connected. But it didn't. The water stopped once it reached the bottom of the skimmer and I pumped the rest out. There was an enormous amount of water that came out of the lines and I wonder if many of the lines drained out, because when I went to blow the lines, some water came out, but not a lot.

    I haven't been able to blow the lines from the pump, because it is attached to the lines with an enormous valve fitting. It requires a 5"-plus pipe wrench, which, of course, none of the stores in our area carry. Is there somewhere I can find this? (I've been to Home Depot and the other hardware stores only have something that is 4 5/8" wide, which doesn't fit.

    I also can't seem to get the water out of the bottom of the skimmer. I drained the equalizer line, but there is still water on the other side. Is it possible for me to blow this water through the pump and down into the floor drain in the pool hut? It just seems to come back when I try.

    Also, part of my problem is that the language is still confusing to me. Is a "line" just the piping from one thing (say the pump) to another (say the filter)? Or is it the entire circle of piping? I think I only have one entire circle of piping, because I only have one skimmer.

    In regard to what you said about blowing the lines:

    "I would blow all lines from the equipment pad, set multiport on filter to waste, disconnect the pump and blow in that connection there, it will also remove the water in your filter. Does this mean I don't have to open up the drain in the filter? As you get each line blown free of water, you can go around the pool and plug in sequence. Does this mean that all the holes are open when I start and that I close them one at a time, starting with the one that is closest to the place where I'm blowing or are they all closed but the one closest to the place I'm blowing and I open and close them one at a time? This ensures the air has one last final route to push out any left in water. If you do drain below the returns, you can then add antifreeze in that same line So I add the antifreeze to the last return in the circle of piping and blow it backwards? And then do the same from the skimmer? And do I want this stuff in the heater/filter/multiport? and once mist is showing from all returns, you can then do short bursts on air to get antifreeze to the lowest part of your lines.

    Thanks again for your help.
    Pool: In-ground; 18,500 gallons; painted concrete (I think -- it was built in the 1940s); Triton II Sand Filter, pre-1991; Hayward Super Pump II; Pentair heater

    Spa (separate): in-ground; cartridge filter, 3 Hayward Super Pump IIs (1 for circulation, 2 for jets);Pentair heater

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    Re: Winterizing Concrete Pool - how much water can i drain without risking heaving?

    You are doing it right.
    It's pretty normal to see water back flowing out if returns when draining pools, thus doesn't ensure all water is out if those lines, you were right to continue to blow them free of remaining water.
    I am not sure what fitting is there, maybe a picture would help, it should turn or you could get some 14" channel locks or even an oil filter wrench.
    The filter plug can stay in while blowing, remove it and let what water is left in it to drain out.
    The skimmer sounds like it is plumbed to the main drain. There will be two open holes in the bottom, determine which one is the main drain, stuff 4' of foam rope in it, then plug it. This will allow you to blow it free of water.
    The lines I refer to are in fact, pipes going to returns, skimmers or water features.
    You will want to put antifreeze in the heater, Get all water out, plug bottom connection, tip back and add a gallon. The valves won't need antifreeze but I recommend placing all o rings n a Baggie, any that leve a black residue on your fingers should be replaced come spring.

    I hope I have eased your pain.

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    Re: Winterizing Concrete Pool - how much water can i drain without risking heaving?

    Last year, I did everything but the lines and then gave up and called a pool company. So here I am again. The water level was fine, though, so that is a non-issue this year. There was a gasket problem in the multiport last year and water was regularly escaping from the backwash line. This added to the confusion and has been fixed this year.

    However, even the pool guys said that they had trouble moving water through our lines and I think that this may be because there is an almost 20 foot difference between the water line of the pool (in ground, but on a hill and elevated about 10 feet above the hut) and the lowest lines of the pools (running in the basement of the hut underground about 10 feet). This isn't a gradual decline, but an absolute run of about 10 vertical feet down, then across the pool hut floor, then another run of 10 vertical feet straight up. I think the water and the antifreeze get stuck here and it is very difficult to move the water up the 10 feet of vertical pipe. Does this make sense?

    So, I blew the water with my shop vac from the farthest outlet to the pipes in the basement, opened the drain and let the water out. Then, I blew the water from the skimmer to the floor and let the water out a drain in the piping there. Then, I blew all the lines with only one hole open at a time, which seemed to get rid of the water. However, there was never any really strong "spray," maybe because a lot of the pressure was already gone with the water I let out at the pool hut basement level???

    How do I know if I got all the water out of the lines?

    I tried adding antifreeze to the skimmer and blowing it through the lines so that it would show up spraying out of the open outlet at the end of the line. No dice. I think the water got stuck in the lines in the bottom of the pool hut and just couldn't make it back up the 10 feet. So how do i get the antifreeze through the lines if this is the case?

    And, for example, if I add antifreeze to the heater, how do i keep it from just washing backwards into the pool hut? (As far as I know there is no check valve. Should there be?)

    Thanks for your help.

    P.S. I have no main drain and I've included an picture of my pool set up earlier in this post that shows the direction of the water flow with the pump on, valves, changes in grade, etc.
    Pool: In-ground; 18,500 gallons; painted concrete (I think -- it was built in the 1940s); Triton II Sand Filter, pre-1991; Hayward Super Pump II; Pentair heater

    Spa (separate): in-ground; cartridge filter, 3 Hayward Super Pump IIs (1 for circulation, 2 for jets);Pentair heater

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    Re: Winterizing Concrete Pool - how much water can i drain without risking heaving?

    One more question: I'm willing to buy an air compressor for this purpose, because I can also use it to refill the air on my water tank. Can you give me an idea of the specs I'd need on the air compressor (PSI, HP, CFM, gallons, etc) to deal effectively with my situation?
    Pool: In-ground; 18,500 gallons; painted concrete (I think -- it was built in the 1940s); Triton II Sand Filter, pre-1991; Hayward Super Pump II; Pentair heater

    Spa (separate): in-ground; cartridge filter, 3 Hayward Super Pump IIs (1 for circulation, 2 for jets);Pentair heater

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