can someone help me with my overflow box

It flows up in water level then quickly drains the water below the elbow and it looks like its siphoning but there's a hole drilled on top to stop that. i slowed it down to the point it lightly does that drain but my pump is pumping water out slower then my biocube pump. Do i stay lower rate or do i jump it up to keep up with the siphon? how is it siphoning it has a drilled hole on the top.
-deep blue ready 90g
-1200 gph mag drive

 

Is it makin a lot of gargling noise when it goes down and back upp again?

 

It gargles when it goes all the way down and what looks like the siphons being broken.

 

Get a ball valbe or a gate valve and install it inbyour drain line. Shut it just enuff to stop air but without restricting the water flow. Theres a video of it sone where on my build thread if your still confused

 

Never ever place a valve in the overflow line!!! This is a disaster waiting to happen.

The overflow rate is determined by the return pump flow rate which can be adjusted with a valve on the discharge side of the pump, never on the suction side and never on the overflow box.

Sounds like you need a standpipe in the overflow box with an air source so you get laminar flow down the overflow. It will solve your problem. Research standpipes such as Durso, Stockman etc. They eliminate the surge action and the noise that goes along with it. As long as the overflow box is sized properly so your pump will not outrun it youir problems go away forever. You cannot use two valves, one on the overflow and one on the pump and balance things out, it will not work for long and you will eventually have a flood on your hands.

 

+1000 to what AZ sez...get a low-noise standpipe and tune it to your system.

Here's an article on making DIY Durso-style standpipes:

DIY STANDPIPE

Note that we no longer use the long intake strainer (it was an idea for a SH setup to catch fry)...I spent too much time cleaning it!

 

The Stockman design is much more compact and completely silent.
R. Durso's 180g - Ken Stockman Standpipe

Durso & Stockman Standpipe

 

if you are not the handy type you can just place a Maggie Muffler on the top of the PVC pipe going to the bulkhead

 

I simply fixed this by making the hole on top 4x bigger and it works fine now however now it makes whistling noises from the grooves from the drill bit but otherwise I'm good now.