Mesh safety cover 101. Need help.

[psihiart]

Hi, This is my second year with 20 by 40 inground pool and I'm confused with using my green safety mesh cover. It is permeable and I have no problem with rain. But in a winter with somewhat heavy snow accumulation it caves in and looks kinda scary to me . It has spring clips and ancors in wooden deck and some in concrete.
I'm in CT. This weekend we had heavy snow with ice. Not a lot, just about 2 inches. But it was enough for my cover to cave in. I just made my water level below returning lines while winterizing.

How it's supposed to be? Is mesh cover supposed to cave like this? Should I make straps shorter so it's not gonna cave in?

 

[bmoreswim]

Caved in is probably the wrong wording, but the concept is the same. Yes, it should look basically like that. The cover is intended to expand the springs on the straps and drop down to the waterline for support. The laws of physics prevent the massive weight of just a few inches of snow from being held in the air by the spring tension. It relies on the water supporting the weight of the snow covered cover. Your cover manufacturer provides a recommended maximum distance between the waterline and the top of the coping. Lowering your waterlevel more than this can void your warranty and allow for undue pressure on the straps/springs. There is no need to drain below the returns. The principle is to blow out the lines and plug them. The water level at least needs to be below skimmers. YOu would usually go down farther than that to allow for rain/snow to bring it back up. But you generally should count on draining out some water between closing and opening to keep the water in the proper range.

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Also, your second strap up in the first picture looks to be loose or broken, allowing the cover to pull in farther then intended. That could be because of the water level being too low and causing excess pressure.

 

[bmoreswim]

See here for some further discussion and a pic. http://www.troublefreepool.com/threads/53452-Pool-Build-Baltimore?p=594036&viewfull=1#post594036

 

[psihiart]

Thank you , I feel better already. I got my water level below returns because i was told to do so by previous owner. He claimed he always did that. he told me it's not good when water frozes around intake and return ports and might lead to damage due to ice moving. I have no idea, I'm new to this.
Would you reccomend to bring water back to be just 4 inces below the skimmer?

 

[bmoreswim]

Only if the water lines are blown out and plugged. Are they? And your mentioned water level is probably too high. Having water below the returns may be a method of winterizing but not a good or reliable one. Was the pool professionally closed or did you do it yourself? I'm not an expert on closing but others here are that can chime in too.

How far below the surface of the coping is the water now?

 

[JamesW]

The water level is too low for that cover. To support a snow load, the cover needs to be able to touch the water before becoming overstressed. Plumbing should be blown out and plugged.

The cover is overstressed now. Also, the straps seem too far apart.

How old is the cover?

What is the spacing of the straps?

 

[bk406]

James is correct. Your water level is too low. I only lower my water level to just above the bottom of the skimmer. In other words, I have water in the skimmer. It's ok as long as the gizmo plug is in the skimmer. My returns are cover with water. I blow the lines wet.
Put some more water in the pool

 

[psihiart]

The water level is too low for that cover. To support a snow load, the cover needs to be able to touch the water before becoming overstressed. Plumbing should be blown out and plugged.

The cover is overstressed now. Also, the straps seem too far apart.

How old is the cover?

What is the spacing of the straps?

The spacing correspondents to the anchors , I've disconnected some to loose the tension .

The cover is not too old, I think .It has couple small holes, but looked and perfomed OK until now..

Yeah , I can see that I put water level too low. I've ordered some antifreeze to put in a lines to be on a safe side. The lines are blown already.

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James is correct. Your water level is too low. I only lower my water level to just above the bottom of the skimmer. In other words, I have water in the skimmer. It's ok as long as the gizmo plug is in the skimmer. My returns are cover with water. I blow the lines wet.
Put some more water in the pool

I can see you are even further north then I am. Thank you for advice.

 

[bk406]

Put some water back in the pool. Leave about a foot to 15 inches below the top of the pool. Re-hook the straps you took off so the cover will work properly and you'll be good.
The cover is designed so the majority of the weight of the snow will be held by the water underneath. I had 4 feet plus of snow on mine last year and it was fine. My water level was/is about 1/2 to 3/4 down the skimmer.
Antifreeze is ok to use but even at our lattitudes it's a bit over rated. If the lines are blown, the only water potentially left in the pipe is basically at the lowest point of the pipes underground. For most, that's at least 3 feet most likely. I've never seen the frost line get that deep in Massachusetts. Water lines have to be 5 feet, but that's deeper than it will ever freeze here.

 

[grottoguy]

bk406, you indicated that you lower your water line to just below the bottom of the skimmer. My pool is closed but I am guessing that the bottom of the skimmer is about 9-10 inches below the top of the pool. I mention that because you also suggest that thevwater should be a foot to fifteen inches below the top of the pool. That confused me so I wanted to ask what I am misunderstanding. Thanks

 

[bk406]

Sorry for the confusion. I don't lower the water below the skimmer. I leave it around 3/4 from the top of the skimmer. I other words, there is water in the skimmer, but lower than it would be when I have the pool open. I find that's about the right level to hold the snow load I usually get. In the end, rain and snow are going to fill up the pool over the winter anyway. I pumped out about 5 inches of water a couple days ago to get the level where I wanted it. After the end of the month, it normally freezes up. Although so far it's been pretty mild. This winter I'm not expecting it to freeze too deep.