Ok, I am not the sharpest knife in the draw, but I need some help understanding this.

In the installation instructions it states:

The solar system works best at flow rate of 1-4 gpm. To regulate flow, simply document the pressure on the pressure gauge of the filter with the by-pass valve open and the pump running. Then throttle the by-pass ball valve closed until the pressure on the filter gauge has increased more than the originally documented........Additional fine tuning may be required.

Ok, how am I supposed to figure out the pressure increase on the filter gauge vs gpm flow thru the panels????

I have 1 1/2" pool lines, a 1 hp hayward pump.

Thanks for any insight you might have.

TRHOD