Odd overflow/gate valve behavior | Reefer 250 G2

[BetterJake]

RedSea G2 with a reefmat installed

I have an issue where the water level slowly rises, I open the gate valve slightly open to lower the water level. I do this multiple times over the week as the water continues to rise. After a few days, suddenly, dramatic decrease in the water level of the overflow and have to massively close the gate valve. What would be causing this?

 

[lapin]

It might be that air is somehow building up in the drain pipe and when water level get real high it purges that air out.
Just a guess......*_@

 

[BetterJake]

It might be that air is somehow building up in the drain pipe and when water level get real high it purges that air out.
Just a guess......*_@

That was my thought as well, but I assumed once it was purged the first time I would be good. 2nd week in a row this has happened

 

[RocketEngineer]

How many pipes are in your drain configuration? 2? 3?

 

[BetterJake]

How many pipes are in your drain configuration? 2? 3?

2, main + emergency

 

[twentyleagues]

That was my thought as well, but I assumed once it was purged the first time I would be good. 2nd week in a row this has happened

Is the drain below water level in the sump?
Most of my tanks I have run have a main syphon and an emergency drain, it seems I have always had to tweek the adjustment on them every once in a while one way or the other. 1 of my tanks had a bean setup this one I never had to adjust once it was set right.

 

[RocketEngineer]

If you make any small adjustments, give it 24-48 hours to settle. Sometimes small drifts take time to work out. But it should balance fairly closely.