Overflow flow ratings

[ajones2n]

Hey guys how do the flow ratings of overflows work? is it more the size of the overflow plumbing diameter or the overflow box, or the overflows built into the tank?

 

[BODI]

A combination of all of the above I suppose, bulkhead fitting diameter would seem to be the ultimate limiting factor.

 

[BODI]

A combination of all of the above I suppose, bulkhead fitting diameter would seem to be the ultimate limiting factor.&nbsp;<br type="_moz">

 

[ajones2n]

so how do they correlate? I can come to an assumption about the bulkhead size contributing to the outcome, but if I had two 3/4" overflows how would I determine the flow rate?

 

[BODI]

Sorry about the double-tap... the overflow design in itself will play a large roll. Stockman, Durso, Herbie, Bean-Animal... those are the 4 most popular designs I am aware of.

 

[BODI]

Some overflow plumbing designs allow for a "full siphon", which can effectively move a much higher volume of water in comparison to a design that only allows a waterfall to trickle down the interior of the drain pipe.

Another thing, high water flow through the sump is a common misconception. Think of your sump as a rest-stop on the road to better water quality!

The slower the display water passes through your sump, the longer your skimmer has time to properly interact with your tank-water and do it's job.

 

[McAllyn]

so how do they correlate? I can come to an assumption about the bulkhead size contributing to the outcome, but if I had two 3/4" overflows how would I determine the flow rate?

Assuming a standard drain design without a full siphon, typically a 1" bulkhead will drain up to 700gph. A 3/4" bulkhead will max out around (maybe just under) 500gph. There are a lot of factors to change this, but these are numbers I've actually tested using Durso and Stockman drains.

Mac

 

[ajones2n]

So what kind of overflow would this be considered? I have a dual overflow what (in your best guess) would the rating be if this system?

Btw they are plumbed into 1" bulkheads.

 

[ajones2n]

I know.... I need to get lots and lots of vinegar and start cleaning. :squigglemouth:

 

[McAllyn]

Looks like a Durso

 

[ajones2n]

I'm gonna sound really dumb in asking this but what's a durso?

 

[BODI]

Yes, that is the "Megaflow" overflow kit used by AGA/Aqueon which is based on a improved Durso design.

Are you trying to determine what GPH return pump to run?

 

[ajones2n]

You guessed it. lol Guess I could have just come right out and asked that.

 

[ajones2n]

So based on what I've read on the flow ratings I've bought an eco1584 for my return pump. Should be adequate right?

 

[BODI]

Did you get your pump all hooked up?

Looks like that pump is rated 1584gph @ 0' head and should put out close to 1200gph @ 5' which is more than enough... You will probably want to plumb a ball valve at the pump output so you can further reduce the flow if needed.

 

[ajones2n]

I haven't yet. I'm dry fitting all the plumbing together planned on having a double union ball valve on each return.