Top of pool freezing, should I worry?

[jmac64]

First year with a pool and I am getting some mixed information from local pool builders on how concerned I should be with ice on top of pool. I have a partially inground gunite pool on a hillside, that faces north. North side of pool looks like an infinity edge, but the pool does not spillover. Pool has no deck on the northside, if that makes sense. Pool is open all year round and I run an automated freeze protection controlled with Omni Hub. My question is how concerned should I be with the top of my pool freezing during extreme cold spells? We had some temps dip into the single digits for a few days and I had a good 4" of ice accumulate on the top of my pool. Pumps stayed running and the water did not freeze at the skimmers, spa spillover or the floor bubblers, but the rest of the top of the pool had a good 4" of ice and the spa had about 1". I have read that the ice on the top of the pool is not an issue, but I have also been told that I should break the ice if it starts to build up. My pool being on a hillside and partially above ground on 1-1/2 sides, I did not know if the ice could be a structural concern pressing on the gunite shell without having fill on the outside? Is the tile at risk with the freezing water since the water level is above the tiles?
I have considered running my heater to keep water temps warm enough to not worry a bout it, but my Hayward heater manual says to not use the heater for freeze protection. Just trying to get some feedback from folks with experience of their pool freezing over while running pumps with freeze protection.

 

[HermanTX]

I would not turn the heater on as that could cause damage to the heater.
It is good that your skimmers have not frozen. Is the ice in front of the skimmer pressing on the inlet and weir door? I would try to break that up so your skimmer does not get damaged.
Have you noticed any tiles that may have cracked due to the force of ice?

 

[jmac64]

Ice has all melted now. It was gone in 48 hrs. Ice never built up around the skimmers. Where water flow was strong by spillover, bubblers, and skimmers, the water never froze. Tiles did not get damaged from what I can tell. I was more curious on if this is an issue that I should worry about with future freezes. We do not get a lot of bad freezes here, but they do happen every so often. If I should be concerned about the ice damaging the pool shell and tile, I was planning to run the heater prior to the cold weather getting here to maintain a water temp in the upper 30's or low 40's.

 

[JoyfulNoise]

Ice has all melted now. It was gone in 48 hrs. Ice never built up around the skimmers. Where water flow was strong by spillover, bubblers, and skimmers, the water never froze. Tiles did not get damaged from what I can tell. I was more curious on if this is an issue that I should worry about with future freezes. We do not get a lot of bad freezes here, but they do happen every so often. If I should be concerned about the ice damaging the pool shell and tile, I was planning to run the heater prior to the cold weather getting here to maintain a water temp in the upper 30's or low 40's.

The problem with running a gas heater with low inlet air temperature and very cold water running through the heat exchanger is that you will generate a lot of combustion gas condensate. That condensation can be very corrosive and in most gas heaters it has no where to go so it will sit inside the heat exchanger. The combustion condensation can cause corrosion of the heater and lead premature failure. It’s just not a good idea.

The bigger concern is your above ground plumbing. It can freeze very fast if the pump stops running. Diverter valves are the most susceptible to freeze damage. The best thing you can do is learn how to completely drain your above aground plumbing and equipment so that when the power goes out, usually at 2am, you can save your equipment. Knowing how to drain the pool a little and winterize the skimmer is important as well.

Ice on the surface of the pool is less of a concern. If you can break it up and keep it from forming a solid sheet, that’s great. But don’t injure yourself in the process, it’s not worth it. Sure, tiles can get damaged but they can be fixed cheaply relative to broken pumps and cracked plumbing.

 

[Toxophilite]

Ice has all melted now. It was gone in 48 hrs. Ice never built up around the skimmers. Where water flow was strong by spillover, bubblers, and skimmers, the water never froze. Tiles did not get damaged from what I can tell. I was more curious on if this is an issue that I should worry about with future freezes. We do not get a lot of bad freezes here, but they do happen every so often. If I should be concerned about the ice damaging the pool shell and tile, I was planning to run the heater prior to the cold weather getting here to maintain a water temp in the upper 30's or low 40's.

They also make floating aerators/fountains for above ground pools that hook to a return via hose. The cheap one I had was dependent on pump speed and no volume adjustment outside of that, but one you could put in problem areas would circulate warmer water from return to surface for that area I would think.

 

[Bperry]

One issue to be aware of is ice forming near parts of the plaster that are horizontal (like steps). I lowered my water down just below the first step and when it froze, I’ve got some plaster chipped off. I suspect the big ice sheet added some pressure in a “not helpful” direction which made the chips. So I’d recommend keeping any horizontal plaster surfaces either well above or well below the surface.