Originally Posted by
wolfeman131
I wouldn't bother with the additional pump. I was set to put one in, but that light bulb went off above my head about the timing. For you, you're going to fill at least an 1,110 (probably plus a 370) off of a single pump. So, that's you baseline, if you will. What do you gain by adding a 4th pump to fill a 650 IBS? Nothing, IMO, except complexity & cost.
If it were me, I'd run the post side off one pump (1,470 lbs), the starboard off another (1,470 lbs) and your IBS (650 lbs) and center (not sure what you have, but I know it's not 820 lbs which is the delta between 1,470 & 650) off the 3rd pump.
Does that make sense? You don't gain any time filling the IBS off a dedicated pump. Your center & IBS will be full while you're still sitting around waiting on the 1,100/370 combo for whatever side you want to surf.
Now, you can get all fancy and set up Y valves to run 2 pumps into a side or to run from one side back to the other - which might be cool for you, but in the end, Moombadaze gave me the best advice before we started my project:
KEEP IT SIMPLE.