Alright, another question due to first large tank.

I know that the sump turnover only needs to be 3X to 6X your total volume which for me is probably around 300 gallons or so counting a sump and refugium. Let's say 5X to be safe. So I am looking for a pump at about 1500 gph at 4' head (from bottom of stand to top of return.

Now what I don't know is how much more head loss do you incure through having dual returns? Seems to me the basic answer is 2 X head for one return but then again that may be too simple.

Just wanting to make sure I get a proper size pump. Looking at:

Iwaki MD70RLT (1500 gph)
Little Giant 4-MDQX-SC
Pan World 100PX-X or 200PS (from what I have read I am leaning toward a Pan World)

Wish Eheim made some larger pumps, loved my 1260 on the 75 gallon.

Thanks for advice!!

Lee