So, my pool is bathwater hot. ick. What would happen if I poured some liquid nitrogen into the pool? I saw some videos, it was a nice smoke/vapor show. But would it do any significant cooling? I could only get a gallon or so at a time though.

Did you take a look at this thread? dry-ice-t18693.html

It wouldn't be worth it. You'd be better off investing in a solar system and using that at night to cool the pool.

I am pretty sure there is a "You might be a redneck......" joke in there somewhere. I just have to think about it for a bit.

I poured a bunch of liquid nitrogen into my pool. It was a cool display!

But as for cooling it down, no, not at all. The specific heat of water is really high. It has so much thermal inertia that it'd take enormous amounts of even super cold liquids to make appreciable differences in pool-sized bodies of water.

Uhhhhhhh................does it come in red and blue for the 4th? I would never be asking for myself of course

Thanks for the input. I thought that it wouldn't work for one reason or another, just thought I would float it out there.

You could create some sort of aerating device to increase the evaporation of water, which will help cool the pool.

However, it will cause your pH to rise due to loss of carbon dioxide and it might cause increases in calcium and TA if your fill water is high in those because you will need to refill water lost to evaporation.

I use a simple PVC pipe that pugs into my Polaris socket and with the booster pump on it creates about a 20' fountain. The falling water is several degrees cooler and over time cools down the pool very well. There are quite a few threads on here with pictures if you want to search.

I personally set my timer to run and cycle water at night and that helps keep the water quite a bit cooler...

I purchased a pair of these a few years ago. They look ungainly but they work surprisingly well. I have used them several times, most recently last weekend - when the water temp of my ~16,500 gallon inground had reached an unrefreshing 90 °F. They lowered my water temp 5 °F overnight. Take only a few minutes to install into your returns. If you think they're ugly, don't worry - they work best overnight, so you can remove them in the morning. The only trick is to partly or completely close some or all of the other returns to increase the pressure from the returns in which you have installed the cooler pipes. I have also found them very useful when lowering TA via acid/aeration. I'm about to install them again, my water temp is 89 °F and the forecast is for 95 °F tomorrow and 100 °F on Monday. You could probably fabricate your own, but in my opinion it's not worth the trouble at a cost of ~ $35/apiece plus shipping.

My pool can easily loose 5 degrees overnight without anything running at all. I run the fountain during the day to keep the temps from from climbing too high in the first place and you'll get a lot more evaporation and thus cooling from that.

I'm not so fortunate. My pool is located in a half walk-out which mimics a solar oven. Imagine a large concrete patio between the house and the pool deck, which is also concrete and girdles the entire pool at an average width of ~ 3.5'. Then imagine long architectural masonry block walls on each end of the pool, one 8' tall and the other stepping down from 6.5' to 3.0'. Add a SSW exposure and stir, and the ambient air temp in the pool area can easily exceed 120 °F on a 100 °F day. As a result, my water temp doesn't drop much overnight during hot spells - all of that concrete and block radiate heat all night long. The upside is a slightly longer pool season - even without using my heater.