rising and falling water level in overflow

[swpassion]

I have a problem, 1 of the overflows in mr tank has an issue. The water level rises and falls, causing big gulps of air and making LOTS of noise. There are 2 on the tank, 1 stays level and causes no issues, the other fluxuates up and down about 3" total. The overflow fills then drops in level. I checked the grids to make sure there is no blockage.

[swpassion]

Anyone??

[MarineBiology!]

are the overflows at the same height? have you tried adding more water to the tank to compensate for the drop?

is the tank level?

[swpassion]

The tank is not perfectly level, but not far off, it was when set up but settled a bit. did not try adding more water, I thought it would just end up in the sump.

[dwd5813]

is the end of the drain submerged?

[swpassion]

Yes, it is a pipe that goes to the bottom of the sump, it is open on the bottom ad has sllits in it, all are below the water level in the sump.

[Sisterlimonpot]

Are both overflow the exact same?
Your pump isn't keeping up with the draining back down to the sump.
Can you increase your flow to the DT?
If not:
As long as you have 2 overflows try putting a ball valve on the one that isn't consistent and close it just enough to stop the rise and fall of the water level.

[MarineBiology!]

is there a way you could add a flow control or raise the lower overflow(if that makes sense)

to me it sounds like the angle is not allowing the water to leave through both flows evenly. if you slow down the one which is not making noise, theoretically it should put the other one to work which would quiet it down. try to restrict flow on the quiet end, it should make more water go to the opposite end

[Sisterlimonpot]

Originally posted by MarineBiology!
is there a way you could add a flow control or raise the lower overflow(if that makes sense)

to me it sounds like the angle is not allowing the water to leave through both flows evenly. if you slow down the one which is not making noise, theoretically it should put the other one to work which would quiet it down. try to restrict flow on the quiet end, it should make more water go to the opposite end

Yep MarineBiology right, I meant to say it the other way around. put the ball valve or gate valve on the one flowing right.

what I meant to say:
"As long as you have 2 overflows try putting a ball valve on the one that is consistent and close it just enough to stop the rise and fall of the water level."

[swpassion]

I will give that a try, I have some ball valves now I just need to figure out the best way to plumb it.

[dwd5813]

rising and falling is a result of air becoming trapped in the overflow tube. as it accumulates the flow slows through the pipe and builds pressure, resulting in the water level rising in the overflow. once enough pressure builds up, the air bubble gets flushed out and the level in the overflow drops again. adjusting the end of the drain can help that out, as well as making a hole in the top of the u and adding an airline there with a control valve to adjust the amount of air going along with the water.

[dwd5813]

i also wouldn't recommend restricting your drain in any way. level the tank if it's not level, don't put something in the drain line that could just end up getting clogged should a big chunk of algae or a snail or fish wind up taking a ride.

[Sisterlimonpot]

on 1 drain/overflow I wouldn't recommend a restriction but for 2 it will be fine.
Think of how many people out there that only one drain/overflow and what would happen if that one clogged. swpassion still has a better chance of avoiding a flood than those with just 1.

[Steve175]

I agree w/ dwd5813: Don't restrict outflow of either (asking for trouble - trust me, I've flooded more than 1 house). You need a Durso standpipe (can search here or google) in order to break the suction that is causing intermittent lowering of water level and the associated toilet flushing sound. Easiest thing is to add a T on the overflow with one continuing down to sump and other extending up above level of overflow water level - higher pipe is capped but is either drilled with an appropriate sized hole (start small and increase slowly to find "sweet spot" where suction is gone) or small valve is added (start with it closed and open slowly to find same sweet spot). Basically, the idea is to allow the perfect amount of air through the higher pipe to prevent intermittent suction from a pure water column draining into sump. My guess is that if you do this for the one causing trouble, you'll then want to do it for the other as well because it's easy to do and leads to much more quiet flow. 2 cents. Steve.

[swpassion]

It currently has the all glass standpipes, is it better to switch to the durso's? The only difference I can see is the durso does not have holes in the sides near the top like the all glass ones do.

[swpassion]

Actually they are megaflow standpipes, not all glass, sorry

[louisvilleboy]

i just had the same problem do not put ball valve on it drill hole and insert 3/8 id in it my right over flow was fine my left one was up and down now its fine trust me hole with tubing

[swpassion]

Originally posted by louisvilleboy
i just had the same problem do not put ball valve on it drill hole and insert 3/8 id in it my right over flow was fine my left one was up and down now its fine trust me hole with tubing

Got any pics? How long is the tubing?

[cdbias2]

It all has to do with how your drain lines are plumbed. One has a larger belly than the other. By "Belly" I talking like the trap on a sink drain..

[oldsaltman]

The depth of the drain lines into the water in the sump may also affect this. I solved a similar problem by raising the drain lines an inch or so in the sump. I also drilled a couple of small holes right below the water line in the sump to let trapped air out of the lines. That would reduce some of the back pressure on the drain line. I use Beans three drain overflow system and got that information from the post on his system.