here is my wet/dry setup:

LF2 wet-dry wet/dry trickle filter
I have the LF2-300

yes I agree, I will prob. put a ball valve on the one side to restrict flow in case it's too much...

its hard to use that calculator with pumps that are not listed...since I was looking at a possible Reeflo Wahoo or Marlin...i'm not sure what the total head pressure loss would actually be...

since this calculator takes in consideration the curve of the pump by model...

I guess I'd have to find the equations used and do the math myself to get to total head loss using the above referenced pumps..correct?

one other thing I don't understand....if I input two exits in the calculator, the number is much greater than if I was to input just one exit and divide it by two for the two returns...

not being a math genius nor a physicist by any means of the word..how does this work...or better yet, should I input 2 exits and go off that number or input 1 THEN divide the total head loss by 2 to get my final PER RETURN

GPH...?