The extra parts arrived and all of the piping was finally connected with minimal leaks. Not without several issues however.
I had the bypass valve assembly ready to install.
Unfortunately the plastic that the reducers were made from did not hold using pvc glue. The union blew apart when I turned on the pump. I also had left the piping overnight without noticing a bad leak at the return pipe.
The pool leaked several inches of water as a result.
I was not sure what to use the connect the two pieces of tube from the filter to the bypass valves. It turned out that the discharge hose was the right diameter so I clamped a short piece between these pipes. There is no strength in pvc discharge hose. So I had to prop the valves on a piece of plywood.
While shoving the filter and pump into a new position I didn’t notice that I had kinked the supply inlet hose. That kink caused flow issues.
Once the piping was together and water flowing I set the Hayward valve to send the water through the solar panel. I can feel the water in the panel moving through the piping by thermosiphon as planned but the heat is immediately taken from the exchanger so the pipes stay hot but the exchanger is cool.
I also have a dripping leak at the pool water union that no amount of tightening seems to help.
Although in sunny weather the system seems to be helping to warm the pool, we have had several cool cloudy days and cold rain that is competing with the sun for heat.
The solar pool circulation is set up for now and I hope I can fix the few dripping leaks eventually.