Overflow VS. Return Pump.

[Malifry97]

I’m looking to build a sump. How do I decide how big to make my overflow and how do. I decide how many gph for return pump. How do I figure out how much of each?

 

[Malifry97]

Bump

 

[ca1ore]

Figure out your turnover goal based on the display tank size, then assume an overflow can handle about 50 gallons per hour per linear inch - that’s the rule of thumb I always use.

 

[Malifry97]

Figure out your turnover goal based on the display tank size, then assume an overflow can handle about 50 gallons per hour per linear inch - that’s the rule of thumb I always use.

ok thanks

 

[mfinn]

For return flow I base it on 3x to 6x the tank volume.
For the overflow size, I've always used the calculator on reef central.

Drain/Overflow Size

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www.reefcentral.com

 

[Malifry97]

For return flow I base it on 3x to 6x the tank volume.
For the overflow size, I've always used the calculator on reef central.

Drain/Overflow Size

Joomla! - the dynamic portal engine and content management system

www.reefcentral.com

Thanks!

 

[WVNed]

Figure out your turnover goal based on the display tank size, then assume an overflow can handle about 50 gallons per hour per linear inch - that’s the rule of thumb I always use.

I am pushing 3500gph through 24 inches of weir. Your rule of thumb seems excessively conservative

 

[ca1ore]

Your rule of thumb seems excessively conservative

Not to me, it isn't. But I do tend to err or the side of conservative with these kinds of things - so guilty as charged ! There are also other reasons to prefer less gallons per hour per linear inch. My current overflow is 36" long and rated at 3,600; but I prefer to run it at half capacity.

 

[WVNed]

Mine is rated for 2400 gph but I tweeked it a bit.

 

[lapin]

I’m looking to build a sump. How do I decide how big to make my overflow and how do. I decide how many gph for return pump. How do I figure out how much of each?

Also when building a sump be sure to calculate for drain back from not only your piping but what will back siphon from the tank.

I push about 3600 thru my 40" weir. The egg crate screen for it also serves as my algae scrubber

 

[Silent]

Reefers used to want 10x turn over through the sump but I think nowadays most are going with half that.

 

[Malifry97]

Also when building a sump be sure to calculate for drain back from not only your piping but what will back siphon from the tank.

how do i do that?

 

[lapin]

Pipe

Pipes with Water Content - Weight and Volume

Estimate water content in pipes - weight and volume.

www.engineeringtoolbox.com

Then you will need to look at your return pipe's exit depth in your tank. Until that pipe or pipes suck air it will siphon back water into the sump. Some people will drill a hole near the water line to prevent much water from siphoning back into the tank

 

[ca1ore]

how do i do that?

Figure out the low drain down point of the tank - that's probably the return nozzle, but it could be the bottom of the overflow teeth also. Based on internal tank dimensions multiply length x width x amount of drain down and then divide by 231 to give you gallons. For example, in my tank the internal length is 94 inches and the internal width is 34 inches. When my pump stops, I get slightly less than one inch of drain down. So, 94 x 34 x 1 / 231 = 13.8 gallons ….. round up to account for water volume in the return and drain pipes and it's 14 gallons.

 

[Malifry97]

Pipe

Pipes with Water Content - Weight and Volume

Estimate water content in pipes - weight and volume.

www.engineeringtoolbox.com

Then you will need to look at your return pipe's exit depth in your tank. Until that pipe or pipes suck air it will siphon back water into the sump. Some people will drill a hole near the water line to prevent much water from siphoning back into the tank

ok thanks for the help

 

[Malifry97]

Figure out the low drain down point of the tank - that's probably the return nozzle, but it could be the bottom of the overflow teeth also. Based on internal tank dimensions multiply length x width x amount of drain down and then divide by 231 to give you gallons. For example, in my tank the internal length is 94 inches and the internal width is 34 inches. When my pump stops, I get slightly less than one inch of drain down. So, 94 x 34 x 1 / 231 = 13.8 gallons ….. round up to account for water volume in the return and drain pipes and it's 14 gallons.

Ok thanks for the help!

 

[mfinn]

how do i do that?

What I do is more of a trial and error method.
First I set the return nozzle in the tank as high as it will go without causing bubbles on the surface.
Then fill with water ( part of my freshwater testing ) and fill the sump with water about 2" above the return pump suction, then turn the pump on. If the pump starts sucking air add a little more water so that it's a 2" above the pump.
With the overflow full and running, mark the level in the sump ( tape or sharpie), then turn the pump off.
The inches of water that returns to the sump is the room in the sump you need to make sure is available all the time, and give yourself a couple inches to spare for safety measure.
Do this 2-3 times.

 

[Malifry97]

What I do is more of a trial and error method.
First I set the return nozzle in the tank as high as it will go without causing bubbles on the surface.
Then fill with water ( part of my freshwater testing ) and fill the sump with water about 2" above the return pump suction, then turn the pump on. If the pump starts sucking air add a little more water so that it's a 2" above the pump.
With the overflow full and running, mark the level in the sump ( tape or sharpie), then turn the pump off.
The inches of water that returns to the sump is the room in the sump you need to make sure is available all the time, and give yourself a couple inches to spare for safety measure.
Do this 2-3 times.

OK Thanks!

 

[symon_say]

Overflow should not be a design concern, try to put a bean animal overflow and it will handle all the flow you want from your return.

For return rate, I like slow return rate 2-5x tank volume, and take into consideration some systems require a desire return rate like Triton that suggest 10x.

 

[Malifry97]

Overflow should not be a design concern, try to put a bean animal overflow and it will handle all the flow you want from your return.

For return rate, I like slow return rate 2-5x tank volume, and take into consideration some systems require a desire return rate like Triton that suggest 10x.

Ok thanks.