Purchased overflow, which return pump?

I purchased a PF-800 overflow (got the larger one in case I upgrade my tank down the road). I am now trying to figure out which return pump I want.

My tank will have roughly 4.5 to 5 feet of head, I would very much like to oversize this pump since I plan on upgrading my tank to 75+ Gallons maybe a year from now. I was looking at these pumps:

Rio 3100 UL @ 782 gph - @ 5' approximately 450 gph
Rio 2500 UL @ 900 gph - @ 5' approximately 580 gph

I planned on splitting my return into two lines right before it returns into my tank. I would use loc-lines for this. This once again is for my 40 gallon display, however I plan on upgrading later a year from now.

 

I would get the bigger one and chuck it down to use on the return.

 

That was my plan, how much can u truly limit the pump using a ball valve without damaging it though?

 

I think you got the model #/GPH ratings mixed up in your post. The Rio 3100 output is 900 gph at 0'.

Anyways, my two cents:

You want to put as much flow as possible through HOB overflows so air bubbles don't break the siphon.

I think both of the pumps you were thinking about are a bit small since the PF-800 is rated for a max flow of 800 GPH. I'd get a pump that is capable of at least 700 GPH at 5' head, so look at a Mag 950 or something similar, I don't think Rio makes a pump with that much output.

I have a Lifereef overflow capable of up to 600 gph. I use a back Mag 950 choked back to ~600 gph. I have never had a bubble trapped in it and the siphon has never broken. It's just as reliable as drilled overflows IMO. It does not harm the pump to limit output by that amount. In your case, you would limit the pumps output even less than I do since your overflow can handle more flow.

 

+1

As long as the pump is restricted on the output and not the intake, it will not hurt it.

 

So i guess what your saying is, since my overflow can handle 800 gph, get something with 700 gph at 5 feet of head so that it keeps air bubbles out and to handle the forceful flow I can split the return multiple times with loc lines in each end/middle area of the tank?

 

Eheim 1260 or OceanRunner 2500.

 

I think that is a good plan.

 

Hm, maybe this will even let me not rely on my powerheads so much. Currently got a reefkeeper setup with wavemaker mode on my koralias. However i would really like to customize the flow more.

 

Return flow will also depend on your sump, you do not want high velocity through the sump or you run the risk of microbubbles even with bubble traps and baffles. How big is your sump and how is it configured?

My return flow is about 800 GPH but I have a 30G sump with multiple baffles then split the return into two Loc Lines via a Oceans Motions Squirt two way. This and the two Evolutions 1400's on a RKL wavemaker function every 30 seconds gives me great random flows in the 100G display.