Calculating inflow into sump

[British malcolm]

I'm looking into setting up a 600g tank. I've done some research on the return pump and reading up in best to have 10x volume return so was looking at possibly getting 2 echotec L1's they circulate approx 3100g each. What I can't get my head around is how do I work out what the inflow would be into the sump. I'm not good at physics and all that but if 6200g aren't going into the sump but it's coming out I'm going to come unstuck. Can somebody help me out please. Also am I best to have 2 return pumps or 1 big one, I was thinking of the noise and vibtation. ? And is echotec a good choice.

 

[TylerS]

You might have better luck in a different forum than the led specific one.

Physics says if you pump 6100 gallons into your display tank you have to drain 6100 or else you'll have problems! The L1 product data on this website http://ecotechmarine.com/products/vectra/vectra-l1 shows the pump curve vs head loss. If you have a sump directly under your tank your most likely looking at having at least 5 feet of head loss, which translates to a flow rate of about 2000 gph (not 3100). That's assuming you don't screw up the plumbing. Just upsize the return lines by 1 size, so use 1" pipe directly after the pump because it's outlet is 1", but shortly after that (maybe after 1 foot) switch to 1.5" pipe and use that for the rest of the return. And when you have the inlet into the tank have at least 2 1" pipes (or even more, this is just off the top of my head). That would be for each pump by the way.

I think you would be ok at 4000 gph. I bet you could get away with less than that even. There are lots of pro's and con's to having 2 small pumps vs 1 big one. If you have two small pumps you have redundancy if you plumb it right. You either need a check valve after each pump if they will use the same return line, or you need to have two separate return lines. There's a lot to decide with this. Based on your questions you might want to consider doing a lot of reading before making any decisions (google).