I would recommend a slight change in the setup of the panels,
on the supply end of the first, I would cap the end of the header that is currently tied to the second - this will force all water through panel 1 to the opposing end, where you should then push through the short pipe to panel 2 and cap that side of the input header, forcing all the water through the second panel then back to the pool.
it would eliminate tying the panels together at BOTH the INPUT AND OUTPUT headers, which can cause unforseen problems and or performance issues (not saying it will, but a chance exists.).