how many inches lost from display during power outage?

[kgoldy]

I have a Deep Blue Professional 75 RR, and I'm trying to figure out how many inches of water (or gallons) I should expect to drain from my display when the power goes out. Some say 2" of water will drain down, some say 3/4"...

 

[albano]

I'm trying to figure out how many inches of water (or gallons) I should expect to drain from my display when the power goes out. Some say 2" of water will drain down, some say 3/4"...

They BOTH could be right...every tank is different, depending on your 'plumbing', and if you have a 'siphon break' in your returns ...
how far under the water line is your return?
You will need to test it with a full tank...to be sure you have the extra capacity in the sump!

 

[fishman1069]

It all depends on how long the slits are in that overflow cause thats where the water is gonna stop draining once the return pump shuts off. So to figure out how many gals, you take the width(of whole tank) times the length(of whole tank) times the height(of the slits)and divide that by 231. This should roughly give you the amount of gallons that will drain into the sump during a power outage. You also have to take into consideration any equipment( i.e skimmers, reactos, etc.) that might empty out.

 

[CHEMCHEF]

Depend on how high you have the standpipe raised.
The higher it is the less water you will lose.
I would imagine I used to lose 7-10 gal. when I shut off my pumps on a 72 bow.

 

[Wes]

It all depends on how long the slits are in that overflow cause thats where the water is gonna stop draining once the return pump shuts off. So to figure out how many gals, you take the width(of whole tank) times the length(of whole tank) times the height(of the slits)and divide that by 231. This should roughly give you the amount of gallons that will drain into the sump during a power outage. You also have to take into consideration any equipment( i.e skimmers, reactos, etc.) that might empty out.

Water will drain below those slits if there is no siphon break on the return.

 

[TRIGGERMAN]

I would say not more than 15 gallons but as Albano said and I always do it as well. Test it and make sure by having a large enough sump or tub under there and calculate it that way. It could definitely be more as well if your return siphons also.

 

[125reefer]

and remember if you have a internal skimmer that holds some water as well.when your power goes out the skimmer will realease water into the sump.so make sure you factor that in

 

[jaa1456]

General rule of thumb is 2"s on the safe side, but that is the general and there are always excpetions. Depends on low in the water you have your return line(loc-lines) in the water. Also it will drain up to the slits seeing how you have a hole in the top of your drain pipe, it will break the siphon. It will also drain any water that will go down the drain behind the overflow, but that won't be much. You have the water in all and any pipes that will drain back into the sump as well. Your skimmer won't empty much water back into the sump, it should raise the level in the skimmer with the same level as sump water when the pump is off. In my 65 with the power out I get about 5-7 gallons of return water. The 2 gallon difference depends on where the water level was on the ATO float as well.