How to fix gurgling overflow?

[marfsreef]

This is my first time setting up a drilled tank without a hang on the back overflow. The overflow box itself doesn’t seem to be making the noise, it seems like the gurgle is coming from the siphon in the drain pipe. The previous owner drilled some holes in the cap, but it’s still incredibly noisy. Any recommendations on how to fix it? The noise is driving me crazy!

 

[Glenner’sreef]

There may be a sweet spot to eliminate the noise by reducing the flow going in to the overflow.

 

[marfsreef]

There may be a sweet spot to eliminate the noise by reducing the flow going in to the overflow.

How do I accomplish this, reducing the power of the return pump?

 

[Glenner’sreef]

How do I accomplish this, reducing the power of the return pump?

Some return pumps have a nob on one side or the other that regulates flow. If not hopefully you have an inline adjustable valve between the pump and the bulkhead that you can turn down.

 

[Brandont21]

My overflow is very similar, I used a different style of overflow so i could adjust how much water was going in, which eliminated the gurgling.

 

[marfsreef]

My overflow is very similar, I used a different style of overflow so i could adjust how much water was going in, which eliminated the gurgling.

That’s interesting, I like that a lot. I might try to find a way to use this idea while still having the overflow box.

 

[Brandont21]

That’s interesting, I like that a lot. I might try to find a way to use this idea while still having the overflow box.

The elbow is not glued as well. So you have multiple ways to adjust water flow. Can screw in tip and twist the elbow. Mine sits at about a 45

 

[marfsreef]

I ended up reducing the power of my return pump and putting some tape over all but one of the air holes on the cap and the gurgle pretty much vanished. Not a permanent or perfect fix, but it took the gurgle from a 9/10 to a 2/10 as far as noise is concerned.