sump water volume calculation for power out

So trying to calculate the volume of water I need to account for during power loss. Need to factor this into the sump/refugium build I am planning. Tell me if I am doing anything wrong or an easier way to figure it out.

So I found an equation to figure out volume that should be accounted for but not sure I am factoring everything in or possibly doing it wrong.

the equation says take LengthXwidthXheight of water to lowest overflow/231 will give you the volume

So basically my tank is 72x18x24 (24 does not matter in equation).
The water is about 1/2 up the overflow in the tank

So I figured I will just call that 1"

So 72*18*1=1296/231=5.610gal

Then I figured I should probably also factor in the basic dimension of the overflow and how far up the water is in correlation to the durso pipe.

So basically I figured I need to account for 2.5" water in the 16x6 section

so 16x6x2.5=240/231=1.038

So total volume water I need to factor in is about 6gal of flow to the sump during power out.

So since my sump/refugium is going to be 48x12x16 I need to account for approximately 2.5" of water volume.

Thoughts on this? I am really not a math wizard so any math wizards please recheck me.

 

Looks about right as long as the sump is not sectioned off like a taller refugium on one end. You should have plenty of room since your skimmer will only like being submerged maybe 8+/- inches so the sump will never be more than say 2/3 full when operating.

One inch of the overflow is already accounted for in your first calculation since the 16"x6" was not excluded or subtracted out.

This is also assuming your returns are no deeper than 1" as they will siphon back until they are exposed to atmosphere. In my 100G reef I keep my Loc Line returns 3/4" below the surface so the internal overflow and returns break suction about the same time and I get a maximum of 3.5 gallons back down to my 30G sump. I never rely on drilled holes or check valves on the returns as both are a false sense of security and can and will fail, usually in the middle of the night or when you are not home per Murphy's Law!

 

thanks AZ.

Do you have a build thread going? would like to see some detailed shots of setup

 

+1 on that I would also love to see your setup so much great advice provided from you.

 

I built the current system over 10 years ago. At the time I detailed it on RC but haven't been on there in years. I do have some threads on AZReefs though.