# 1" or 3/4"



## sandeephema (Aug 24, 2007)

I am building a 90gallon tank and filter will be Sump tank.
Please suggest me the plumbing should be 1" or 3/4 is enough.


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## hojimoe (Mar 7, 2008)

depends on how fast you want the flow? I suggest using 1.5" drain pipe, and 3/4" return, you can go upto about 1200 gph I believe with that (from what I remember)

1.5 drain requires 2.5" hole and 1.5" bulkhead


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## _Green_ (Dec 30, 2008)

hojimoe said:


> depends on how fast you want the flow? I suggest using 1.5" drain pipe, and 3/4" return, you can go upto about 1200 gph I believe with that (from what I remember)
> 
> 1.5 drain requires 2.5" hole and 1.5" bulkhead


why make the drain larger than the return? Wouldn't that mean the water could drain faster than it can be returned to the tank?

Sorry if this is a dumb question

Ross


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## ameekplec. (May 1, 2008)

It depends, like JIm said, on the flow you need it to handle. Use an overflow calculator:
http://www.reefcentral.com/calc/drain.php


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## aeri (Sep 9, 2007)

gravity flow

3/4" = 330 gph
1" = 600 gph
1 1/4" = 910 gph
1 1/2" = 1,300 gph
1 3/4" = 1,800 gph
2" = 2,350 gph
2 1/4" = 2,960 gph
2 1/2" = 3,650 gph
2 3/4 = 4,450 gph
3" = 5,280 gph 

forgot where i got this list from. but credit to whoever made it.


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## sandeephema (Aug 24, 2007)

*thanks to all*

Lots of thanks everybody. I think according to the chart poste by "aeri" i shall go with 1.1/4".
thanks again


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## hojimoe (Mar 7, 2008)

_Green_ said:


> why make the drain larger than the return? Wouldn't that mean the water could drain faster than it can be returned to the tank?
> 
> Sorry if this is a dumb question
> 
> Ross


well in reality, yes it can drain faster than you can return to the tank, but on the same note, the tank will only overflow at the rate you "return".... which is why you always make a larger hole than the flow you're returning, just in case of clogs etc.... if you return 900gph, and you're hole is 1 1/4", allowing drainage of 910gph (gravity max velocity), then you're going to run the sump dry if the drain is slightly clogged with algae or something... make it larger

also, when choosing a return line, use a calculator that will determine the out flow, after figuring out the head loss....

example, my mag 12 return pump, can go 1200gph at 0' of head, but the way I have it set up, the max is about 950gph, but I also have it slowed a bit, to 800 or so, so it's very quiet on the drain, otherwise I find there's a little bit of noise coming from it


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## _Green_ (Dec 30, 2008)

interesting, thanks for clearing that up for me.


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## ka NUK (Dec 19, 2008)

Thanks hojimoe ...saved me from typing all that 

Always oversize your return pipe by a factor of 2 or 3 (made those numbers up). It's cheap insurance against a large spill.

Also make sure your sump can't overflow during a power outage. If both ends of your water return hose (from pump to tank) are submerged, you can siphon large amounts of water into your sump.

Don't ask me how I know 

ka NUK

Edit: To quieten the "flushing toilet" overflow: Durso standpipe


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## aeri (Sep 9, 2007)

If you drill a hole in the return line in the tank at where you would like the water to be if the pump were to turn off, it would break the (back)siphon.


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## ka NUK (Dec 19, 2008)

Agreed!

Good thing this thread made me think of this issue, 
as I almost made that mistake.

ka NUK


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## aeri (Sep 9, 2007)

I _did_ make that mistake


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