Thanks, Al. I am understanding that. This is what I plan to do: let me know if it needs correction or more work.

These are on the fence making it look 40' long with a space in the middle of them for plumbing and I am putting the pipes under ground right next to the fence...then up to each panel.

From pool to solar... a "tee" to right panel into right bottom
an "elbow" and up to left panel into left bottom

From solar to pool a "tee" to right panel out of right top
an elbow to left panel out of left top

Both panel ends will be capped... the far ones.

I will put a gate valve in each line just before the elbow going to the second or left panel so that I can use either one or both panels at one time depending on the season and how much I need.

How did I do?
Ellie