We looked into pool covers for our T-shaped pool. A non-rectangular pool such as a kidney can have an automatic cover that runs on tracks in the pool deck. That allows the cover to be a rectangle and run on straight tracks. It wouldn't work for us because there are two large landscaping rocks on our deck. Even if the rocks weren't there, our pool is so far from rectangular that the cover would have to be huge. But it should work fine for a kidney shape pool.

(Browsing on the web now, I found a cover, Hydralux, that might handle even our pool because it's made from rigid hallow slats and has a model that can rise up from a recess in the pool bottom to deploy. However, it looks like it would cost a mint and reliability would be a concern for such a unique mechanical item.)

Oh, that's interesting...I'll have to read up on it.

The rectangular ones with the tracks will be a tough fit--the people who installed this pool in the early 60s chose to stick it in a skinny part of the yard quite close to the house. I like that--I still have a yard!--but it makes landscaping with a pool fence tricky. And it makes covering really interesting.