How high is your water level on the overflow teeth?

[kevensquint]

Building a sump and trying to estimate how much back flow will occur in a power outage. The tank will be about 140 gallons and if the water level drops 2" will lose 15 gallons to the sump. My planned sump could only handle 13. But, if water levelin the display dropped by 1.5" It would work. So just seeing what happens in everyone else's tanks. In my current 75, the display only drops an inch in a power outage, but my return pump is not very strong which explains that.

 

[Oscaror]

1/4 inch for me

 

[kevensquint]

Hmm, maybe assuming my return pump would raise the display by 2" is over estimated. Is there a trick to have high flow all around without backing up the display only to dump a ton into the sump when the return is shut off?

 

[Oscaror]

Let me call the [HASHTAG]#reefsquad[/HASHTAG]

 

[NanaReefer]

Larger return pump. What is your overflow rated for?

 

[143MPCo]

i'm at 3/8" but, push alot of water through my system.

 

[143MPCo]

trying to estimate how much back flow will occur in a power outage

The amount of back siphon is a little tricky to determine, you need to take into consideration the death of returns ling in the display tank water, amount a water left in the return lines plus overflow volume and setup, and amount of water in drain lines. You can mitigate this by adding siphon breaks in key location so as to maintain a greater volume of water in the display tank and out of the sump.

 

[jhoop]

I used black tape to raise the level of the water by covering up half the distance of the teeth.

 

[143MPCo]

In the image below you can see a good illustration of a siphon break, I'm not a fan of them injecting directing into the display tank but, this was the best image I could find to show the point...

 

[143MPCo]

If you need to raise the level of tank water, a cheap easy and most importantly safe way is to use a thin sheet of plexiglass cut to size and siliconed into place...

 

[acidtablockshifty]

too high lol, one day ill somehow cut the teeth a bit deeper to lower the level of my display, it is just a little to high. I think i would just throw on filter socks and double up some hacksaw blades and only cut in the direction of flow, ill probably never do it lol