Why do people use 1" pipe on there return pumps?

SalteeDogg

SalteeDogg

Reefing newb
I have noticed most return pumps are three quarter inch and was wondering why you would need to go bigger then three quarter when you plumb it? Wouldn't three quarter inch pipe create more pressure? Reason I ask is because im setting up my sump and I ran half inch tubing off the return pump since the outlet was three quarter and after looking online at pictures, I have seen most people use 1 inch instead of the smaller. Makes my plumbing look light duty compared to the people who use 1 inch tubing. :grumble:

Also wouldn't you lose head flow with bigger pipe due to the weight of water pushing down on the pipe versus a smaller inch pipe with less water? My overflow is a 1 inch diy pvc but return is half inch pvc. I am wondering if this is right since its on a 160 gal
 
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My return pump is 3/4", so that's what size I'm using into the tank....but my overflows are both 1" each all the way down. Works fine. I only paid attention to head loss for the return, not the overflow.

What pump are u using? How many GPH?
 
mag 7/700 gph with 5 ft to head....I just relized my three quater inch tubing is slid over my half inch pvc. So its almost like I reduced it instead of going bigger. Hopefully this won't mount to anything.
 
The smaller pipe would cause the presure to increase but the flow it decrease also. Think of it like putting your thumb over a garden hose. The water comes out faster and shoot farther.

Also, the head preasure in a column of water is dependant on the depth of the water not the volume. A water column half inch in diameter and 5 feet high produces the same presure as one 1 foot in diameter and 5 feet high

Mainly, people make the returns larger to spread the flow out a bit more so you dont have such a fast current flowing through the tank and makes it more diffuse.
 
I use a mag18 for my 125g, and it's got a split at the pump just after the 1 way check valve, and one return pipe travels 3 feet, and the other travels 6 feet after the split, so I needed that stronger one. Which is why I was wondering why Saltee is using a mag7 if it's for his 160g. I guess you thought I meant you, right, bj? LOL
 
A mag 7 has a turnover rate at about 3 I believe for a 160 which is bare minimum. Salt/reef tanks should have a turnover rate of 10. So a 1800-2400 gph pump should be fine when I switch. I messed up making my sump, I made my bubble trap middle divider too low so when Alot of water comes in it will go over my bubble trap. I'm afraid if I go too big that will be my problem. Plus my dual siphon overflow's probably wont take much more then 1800 gph.
 
I've got a Mag 9.5.. on the instructions it says to use 1 1/2" ID hose for max flow. So that's what I did. Until I put an elbow on it, it would completely blow my sand off the bottom of the tank from 20". And that's with about 6' of head loss.
 
I would never go smaller than the pump outlet as it will increase pressure, reduce flow, increase temps, and wear out the pump. If you go larger than the pump outlet you have the advantage of decreasing the pressure which will reduce wear on the pump, and keep your temps lower.
 
SalteeDogg said:
A mag 7 has a turnover rate at about 3 I believe for a 160 which is bare minimum. Salt/reef tanks should have a turnover rate of 10. So a 1800-2400 gph pump should be fine when I switch. I messed up making my sump, I made my bubble trap middle divider too low so when Alot of water comes in it will go over my bubble trap. I'm afraid if I go too big that will be my problem. Plus my dual siphon overflow's probably wont take much more then 1800 gph.
Click to expand...
A Mag 7 does 700 gph...before head loss. The recommended flow rate thru a sump is 5x-10x the tank's total water volume. If you have 160 total gallons after you added the rock, sand and water volume from your sump, you are looking at 800 - 1600 gph thru the sump.
 
On my 130 I've been using an eheim 1260 which is rated at 635gph and I'm wondering if I should switch to the 1262 which is rated at 900gph. Right now I've got my gate valve on my drain dialed down a little. But I don't want to push too much through my sump.
 
Yeah im afraid of too much flow through my sump for many reasons. Another being that my overflows are going to be LOUD with that much volume of water going through them. I can always do the durso standpipe mod or something but those can be contrary to get dialed in. My overflows are diy pvc and already make minimum noise right now and afraid of them going ballistic. Guess ill have to play it out.
 
anyone know any tricks to keeping these micro bubbles from sneaking through the bubble trap and into my pump? I placed a filter material inbetween which helped but they are still getting by. Do I wrap the pump with filter material? micro bubbles are coming from skimmer and my overflow is shooting them out for some odd reason.
 
don't wrap the pump! You will burn out your pump. The overflow will always shoot airbubbles. That's normal. Just add another baffle to your sump if it's a problem.
 

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