I am a relatively new pool owner. My wife and I bought our first house four years ago which has a 30,000 gallon in ground pool. Not having any pool experience the first few years were rough. Now with four seasons under our belt we have hit a nice groove with maintenance, chemicals, cleaning etc. However the same problem persists each summer of water temperature. It stays below 70 for most of the summer. In late July early August it will spike to 75 but that will only last a few weeks. I can see how awesome it is during this stretch but in general a three week stretch of swimming is a small reward for all the work that is put into it.
I've done a lot of research on how to bring up water temp. We use the solar cover which definitely helps. I've read a lot about solar heaters both DIY and manufactured stand alone units. About a month ago I started my DIY solar heater with 400 feet of 1/2" black irrigation hose. I installed a Y fitting with valves on my Hayward EC65 DE filter. On a sunny day the water does come out 10-12 degrees warmer than what it comes in at. I'm happy about this but the flow rate is down at about 1gallon a minute. With a filter on for 10hrs I get about 2% of total pool volume per day. This is never going to add up to anything real. I could add more irrigation hose but my fear (after going from 200' to 400') is that if I go to 600' that the head loss will be too much and restrict flow even more. I can close the valve on the regular filter outlet pushing all the water through the solar heater irrigation hose but this still only doubles the flow rate to about 2 gallons a minute. It also doesn't give me the warm and fuzzies with the pump low output volume. Another thought is that I could upgrade to 3/4" hose or full inch hose to reduce head loss and increase flow rate. However a quick experiment using all 125' of existing garden hose I have produced similar low flow results.
Am I just nuts for trying to heat such a large pool through solar? Should I look into getting a larger separate pump for increased volume? Should I cut my losses and buy some of the Blue Wave SolarPRO Curve heaters? We have natural gas in the house should I look into a gas unit? I wouldn't say money is no object but my general philosophy is I would rather pay for something that I know will work and do the job.
Sorry for the long post, any ideas and thoughts are welcome.