Urgent: Overflow leak.. Advise required.
 

So I am in the process of filling the Display portion of my tank of which I have dual overflows.

My left overflow appears to be sealed tight so far.. My right one, appears to have a very slow leak.. there is about 6" of water in the display section, and about 2" in the overflow.

I am using a Herbie style overflow.. if my main drain height is equal to the height of lower lip on my return bulkheads, in the case of a power outage, once the water drains to the lowest lip on the return bulkheads (and the highest point on main drain)

Will the water level between the DT and overflow equalize at the same height or will the pressure in the DT push through the leak and Raise the water level in the overflow ABOVE that of the Display area?

My understanding is that because there is a leak, the pressure (and thus water level) between the 2 sections will equalize.

This is all presuming that a power outage occurs and the Display drains to the lowest lip of the return bulkheads which is the same height as the top of my main drain in the leaky overflow, of which the overflow would drain to.. thus, same water level in each..

Correct???

Your overflow water level will never get higher then you display but it will keep draining until the water level is below the shortest pipe in the overflow & display.

Thanks Grizz.. I guess I got some modifications to my standpipe to make tonight.

What has been said is correct. The water level will equalize in the DT and the overflow area.

One problem might be if you ever had a leak in the bulkhead for the overflow you wouldn't really be able to work on it. Your DT would slowly drain into that area.

The other problem may be if you had a leak in the bulkhead in the overflow area and the power went out for a long period of time, your DT would also empty into your overflow.

Scenario 2, 99.9% won't happen, as I had a slight oversight when doing my plumbing and cemented the stand pipes into the bulkheads. :neutral: I left that .1% so I don't sound like a fool in the future when my PVC cement fails me for the first time ever.. :lol:

That leaves your first scenario, which is possible. But I think if the bulkheads themselves leak, it would be manageable to replace them with the aid of a towel so soak up any leakage while replacing. A possible nuisance for sure, but manageable and easy to keep check of on a daily basis. I shouldn't say this, but I have always had good luck with bulkheads not leaking.

The leak is fairly slow.. over the course of 1.5hrs the level in the overflow raised by 1/8" (in a 8.5"x6" footprint).

If power goes out you DT will be still draining in to the Overflow and down to the sump. If your sump is larger then DT you are ok.

But skimmer will overflow as well as whatever else you have in the sump

Find yourself a tube of Orca Glue. It seals underwater and it's safe.

Works like a charm and has saved me countless times :D

Pisces carries that stuff.

Thanks!