What size return pump?

cdnz64

Reefing newb
I have an 800 gph over flow box to my sump and I'm trying to figure out what size return pump I'll need for my sump so that the flow is even. The change from the sump to the top of the tank is approximately 4.5 feet, and I know that there will be a head loss, and will need to compensate for it, but I'm not sure how to figure it.

Also are there any certain brand of pumps you'd recommend?
 
I like the mag pumps. I run a mag 12 and a mag 9.5 in my refuge. I`m thinking a mag 12 with head loss should work but I`m not that smart on plumbing issues. Do you have a ball valve to restrict flow in or out.
 
I like the mag pumps. I run a mag 12 and a mag 9.5 in my refuge. I`m thinking a mag 12 with head loss should work but I`m not that smart on plumbing issues. Do you have a ball valve to restrict flow in or out.

No I haven't bought any of the actual plumbing yet because I'm waiting to see what size of pipe, diameter wise, I'll need. I assume that you can pick up ball valve at any hardware/plumbing store?
 
Hopefully my guru Larry will come on here and post. He really knows this stuff and about lighting. I`ll PM him.
 
Here is a head loss calculator:
http://www.reefcentral.com/calc/hlc2.php

You can use that to approximate how much loss you'll have in the plumbing and vertical height.

Here's a list of pumps and the output:
Reefs.org: Where Reefkeeping Begins on the Internet - Welcome to the Reefs.org Pump Selection Guide

Don't buy PVC at a big box store. It's twice the price of this place:
Buy flexible pvc pipe at FlexPVC.com PVC pipe, hose, & pvc fittings online @ wholesale discount prices (flexable)

As far as your pump size, you need to determine the total head loss. You've got to have a rough idea how it will be plumbed. Count your 90's and 45*s. Plug it into the head loss calculator.

Now that you know how much you're going to LOSE in the pipe, fittings and head, you need to determine how much flow you want in the tank. Let's assume you are talking about a 55g tank. You know the max the overflow can handle is 800GPH. So figure your head loss, pipe loss and add that to 800. Thats the MAX size pump you can run.

I personally wouldn't push more than 700-750gph through an overflow rated for 800gph. I like a safety margin. With my Mag 7 return pump and all the pipe, I am down to about 400gph in the frag tank. My overflow will do 700gph. It's all drained and returned through 1.5" lines. Overkill? Probably. But I have a safety margin that makes me warm and fuzzy.
 
RC,

I'm trying to make sure that I understnad you correctly. I don't want a pump that will do more than 800 gph correct? How many gph do I need to have to keep my water quality good. This is going to be for a 120 gallon tank.

Thanks.
 
RC,

I'm trying to make sure that I understnad you correctly. I don't want a pump that will do more than 800 gph correct? How many gph do I need to have to keep my water quality good. This is going to be for a 120 gallon tank.

Thanks.

According to your first post, 800gph is the max you can run out the overflow. Thats your limiting factor in the whole equation. So size your pipe, pump and bulk heads for 700-800gph.

120g tank x 10 times turnover is 1200gph. 10x is usually the "minimum" turnover for a tank. If you could get 800gph through the overflow, then you'd still need some power heads in the tank to get an additional 400gph of circulation. Or you could run a lower amount through the overflow and do a closed loop. Run 600gph through the overflow and pump 1500gph+ through your closed loop. That would still be less than 20x turnover. Problem with a closed loop is they require a lot of bulk heads and drilling. Expensive. But if you want a clean looking tank without ugly power heads hanging all over the place - it's a nice way to go IMO.
 
RC,

I'm trying to make sure that I understnad you correctly. I don't want a pump that will do more than 800 gph correct?

Thanks.

It needs to do 800gph at the tank. So after all the pipe loss and the head loss, you might end up with a 1200gph pump. But after all the pipe and bends it's only going to be 800gph or LESS going into your tank. Thats your max you can get out of the overflow teeth.

You'll have to use those calculators to figure out how big a pump is required to get you 800gph back in the tank.

800gph in the sump doesn't mean diddly squat. It's got to be 800gph after all the pipe bends and head loss.

My Mag 7 return pump goes through 4' of head, (5) 90's, (2) 45's, (1) ball valve, (1) union and 1' of horizontal run. All in 1.5" pipe. By the time it gets to the tank, it's just a little over 400gph. Now consider that pump is rated at 700gph with no pipe or head loss. Thats what you get right on the outlet side of the pump.

But after all the pipe it's only 400gph.

Use the calculators and fill in the numbers. Draw your design up on paper and measure it all out. Count all the valves, 90's, Tee, unions, pipe and plug it into the calculator. That will tell you how big a pump you need if you want to get 800gph back in the tank.
 
Back
Top