I was on this kick for a while to keep my pool warm (an hour south of NYC), but quickly decided it wasn't worth the trouble and fossil fuels are much easier and straightforward for focused heating (I also have an already installed propane heater, FWIW). But honestly, the best thing that happened was my neighbor cutting down all his trees - my pool now gets sun from dawn to dusk and is always warm enough to swim in (and during heat waves can actually be too warm, 90F+). If memory serves, you've got a ton of tree cover which is never going to work in the northeast.
Also note , the pool industry is having a serious issue with the delivery of parts . Down in Florida , the price of chemicals has nearly doubled on some stuff . Before I left to Biz last June . I couldn’t replace a commercial pool pump or replace the bad pump body with new parts . All the warehouses in my area were out of stock . Had to go to a pump junkyard to rebuild the commercial pump . Also talked to the guy who bought my company the other day and he said it has gotten worse since I left last June .
I've used free-floating black foam diamond plate gym floor tiles to great success on top of having a 100' run of black vinyl irrigation tubing along the top of the metal fencing. Doesn't look horrifically Redneck, and the pool is in the 90s on a Texas August day.