I have a number of questions that I am struggling to find answers to and hope the experienced folks on this forum can help.
Background: My equipment setup is shown in the schematic. My pool is irregular shaped and I guess somewhere around 25K gallons. The solar heater was just installed and I installed the SWG a couple seasons ago. My Nautilus FNS60 DE filter just failed as I tried to open the pool this year. It would cost $200 to replace the clamp band that failed, which is ridiculous, so I am using this opportunity to go to a sand filter. I like to run my pump on low most of the time for 10 to 12 hours a day to give the SWG enough run time to generate enough chlorine. In the diagram, all black piping is 1.5". The return to the pool is 2" and the orange lines for the polaris and booster pump are 3/4". I have pretty much stopped using the propane heater after estimating that heating the pool for a weekend used about $100 worth of propane.
Problem: With the pump on low, the chlorine generator often fills with air or maybe gas from the generator and not all of the generating plates are immersed. When the polaris pump comes on, it drops even more and shuts down due to no detection of water flow. My initial testing with the the solar panels shows that the pressure drop they cause makes this problem even worse.
Question 1: Why does air/gas accumulate in the SWG? Is it a byproduct of the chlorine generation?
Question 2: Is the expansion from 1.5" to 2" pipe after the SWG reducing the backpressure and letting the air build up? If so, should I move the SWG to location C so it is at a higher pressure point?
Question 3: When I reconfigure for the new filter, should I put in a set of bypass valves for the propane heater to reduce the pressure loss it causes?
Question 4: Should I move the solar heater to location A so the booster pump is running water through the panels and not the main pump to remove its head increase from the main pump?
Question 5 Is there a difference in pressure loss between DE filters and Sand filters? Will my pump on the .25HP setting still be able to move water through the sand filter?
Thanks in advance for any assistance!