the current 3/4 hp is actually a 1/2 hp uprated..the new one will be a 3/4 hp uprated to 1 hp.

maybe i'm not explaining myself properly on the valves thing..here's what i know...when i have both ball valves open on the 2 lines labelled skimmer and main (lines that come in from the ground as 2 separate lines into 2 separate valves, then into a T and then into the pump intake i guess you'd call it) i get less pressure in my filter when i have one or the other closed..but note that if i have the skimmer valve open but the main drain line closed, there is more velocity in the skimmer..if i reach my hand in, there is definitely more suction in the skimmer.

so, back to the original question about the new vacuum and should i have enough gpm flow. or maybe i'm making an assumption that extra suction is higher flow rate..my brain hurts now

it sounds like i wont' have a concern otherwise relative to to much pressure for the filter (which is rated for 62 gpm max) with the new pump!