Thanks Mark.

It's more like a 7 psi reduction rather than the 10 psi I originally reported. The in floor system is effectively bypassed. The pop-up heads are removed, but the return still goes through the water valve into two of the circuits. The other circuits are plugged. The two open circuits are both open at the same time, all the time. So from my perspective, they are just pipes that happen to return water to the floor and using the water valve as a manifold. This is the same configuration before and after the pipe upgrade. I haven't even cleaned the filter. I imagine the high pressure from in-floor systems is due to the springs that need to be overcome to get the heads to pop up. Since these are removed, this would not be a factor.

The in-floor fittings will eventually get eliminated and return water will go to side outlets - eventually.

It makes sense that flow and power consumption would increase. I'm already on board with reduced run times from the paper you posted in another thread (and attributed to Doc). I've been running about 3 hours all winter. My water is at 80 degrees now and looks good so far. I may try to run the pump even less with this change.

But the addition of 288 sq. ft. of solar panels (2 inch headers) should increase flow loss back to nearly what it was before, I suspect. That was my thinking anyway. So after solar, run time will be dictated by solar heating or cooling demand during those months that it's needed which will no doubt exceed the run time needed for water clarity.