I agree with you, we don't want to get argumentative, we just want to debate facts and learn from what each other is doing.

When you have many small tubes that equal the same cross sectional area of a larger pipe you do increase resistance to flow. 100 small pipes with cross sectional area of "X" is not equivalent to one large pipe with cross sectional area of "X". That is because there is much more surface are in all those small pipes and you end up with laminar flow at the walls of all those tubes.

Now the difference may also be in that I am running just a small slip stream of the total system flow through the panels and am not trying to run the entire pool flow through them. But that aside, you will always have less pressure drop in a parallel system than a series system. BUT bottom line, if your setup works well for you that is great. I would like if you could post a picture or schematic of it similar to the manual I posted so I could get a better idea of how yours is set up.

Thanks