Help with new reef tank setup

[Justfbilly]

I have set up my 125 gallon drilled reef tank over the weekend. I have a Eshopps RS 200 sump and I am running the Jabeo Dcs 12000 return pump. The drain line from the tank to the sump is a 1 1/4" ID hose and the return line from the pump to the tank is a 1" ID hose. The issue I am running into is I can turn the pump on and the over flow operates normally then it will drain about 3" of water out of the over flow area and start making a bunch of noise and then the water will fill back up to the normal level (but only in the over flow section) and then it will continue to drain and then refill? I have put a ball valve into the return line from the tank to the sump to see if I slow down the volume of water returning to the sump will help. This has seemed to stop the draining and refilling issue in the overflow section but now I am struggling with setting the water level in the sump. It will rise slowly or go down slowly depending on the ball valve or speed of the return pump. With my HOB setup the sump balanced it self out, but I cant this system to work correctly. Any ideas as to what I am doing wrong or what I can do to fix this? Thanks for the help!

 

[Robink]

I'm no expert at the plumbing, with that said...Your pump and overflow should be working together, maybe adjust the level of the overflow box. It may also be the level of water in the tank and sump (maybe not enough water), whatever water is sent into the tank should overflow into the sump keeping the levels correct.
I'm sure one of the plumbing experts will be answering you shortly.