Balancing Water Levels in Back Chamber

[Belwell]

I just set up my 38G AIO yesterday and I'm having trouble balancing the water levels in the back chamber of my AIO. It's a Fuji Cube 38g Peninsula tank.

When the pump is off all of the back chambers have the same water level. As soon as I turn the pump on the water almost completely drains from the return chamber and pumps into the tank. After a few hours of running like this the water level stays near the bottom of the return chamber and the water cascades down creating a lot of noise. I've played with the pump to slow down the return as much as possible, but it doesn't really affect the water level in the chamber. I replaced the pump with a quieter and lower flow pump and got the same results. I could add more water, but I'm afraid that I'll just overflow the tank.

Am I missing something?

 

[NowGlazeIT]

I just set up my 38G AIO yesterday and I'm having trouble balancing the water levels in the back chamber of my AIO. It's a Fuji Cube 38g Peninsula tank.

When the pump is off all of the back chambers have the same water level. As soon as I turn the pump on the water almost completely drains from the return chamber and pumps into the tank. After a few hours of running like this the water level stays near the bottom of the return chamber and the water cascades down creating a lot of noise. I've played with the pump to slow down the return as much as possible, but it doesn't really affect the water level in the chamber. I replaced the pump with a quieter and lower flow pump and got the same results. I could add more water, but I'm afraid that I'll just overflow the tank.

Am I missing something?

I would try to add more water. I always have a float valve at the last chamber that adds water as needed. When you get evaporation you’ll notice the water level in the return/pump section starts to drop.
If your worried about it over flowing then simply turn your pump off and notice the water line drops a small amount in your display as the back chamber fills up. For water to overflow these back chambers would need to be full before shutting the pump off.