Urgent Help with overflow box (video)

Hey guys I have the CPR overflow box for my 55 gallon tank.
Today was my first water change and it went great. It worked perfectly before I changed the water. When I hooked up the overflow box and primed it, I knew it wasn't working well right away. First, the sound from the water hitting the sump was A LOT louder. Second, the water in the overflow box fluctuates and when it gets too low it makes a VERY loud gurgling sound. Could it be that there isnt enough water in the tank? Here is a video that I just took. Sorry the audio is bad.

CPR overflow not working properly - YouTube

 

Mine did this as well when i had my old tank (so glad im drilled now lol) mine always fixed itself after a while. it looks like its flowing into the overflow in the front fine, so i would assume yours is just doing what mine did, but if it doesnt fix itslef in the next day then idk...someone else will have to give advice then haha!)

oh yea, i am thinking for some reaosn the water in your tank would be low and that would cause the flow going in to be wierd, but no thats just me still being awake at 6am and my brain isnt running properly lol. is the water in your sump low?if so thats why it sounds louder...but if not and it doesnt fix itself then i still dont know haha!

 

How much flow are you getting via your return pump?

 

if it were me, I would get a durso or Hoffer silencer in that bad boy. that will solve it. what you are getting is a buildup of air in the drain tube and it is flushing like a toilet. adding a durso or Hofer gurlge buster will fix it. I had a dual one just like this. Great overflows if setup right. I see you have the Aqualifter pump on there. Mine had the dual drain, but I only used one side of it. I used a Durso and it was dead silent and worked great...

EDIT. also, you will want to replace that clear tubing for the pump with black tubing. otherwise you will get algae growth in it and it will clog both the tubing and the pump manifolds. Take the pump off every 6 months or so and completely dissamble it and clean all the baffles and valves. they tend to gum up. or just plan on replacing it annually.

I also see you have some sort of airline in the drain now, you may want to tinker with its height, but a durso (space permitting) or Hofer Gurgle buster are your best options on those drains. I had mine for over 4 years and LOVED it.

 

starts at about 3 min. into the video

50 Gallon Reef Aquarium Day 106, CPR overflow box Durso mod, Pink Cotton Candy Algae! - YouTube

 

Awesome post.. thanks for showing it Chris.