So I've never been too thrilled with the design of the original sump that came with my 90 gallon when I purchased it a few years back. It came with the tank so I wasn't complaining because really I knew nothing at the time about reef tanks and wasn't really sure what my preferences were. The design is a 3 chamber. Overflow to the left. Return in the middle. Refugium on the right. It's terrible for slowing the flow of micro bubbles to the center section due to its lack of bubble traps. I've tried sponges and facing the skimmer outlet as far as humanly possible from the next flow section and I just can't take it anymore. The wall that controls my water level is pretty high too which I've built a skimmer stand that doesn't allow my skimmer much room(1") for removing the lid or neck for weekly cleaning. Plus it's not as pretty as I want. Controlling the refugium section with a ball valve isn't something I'm all too fond of either since the pump I'm using is a seasoned Mag 9.5 that controls not only flow up to the tank but into the fuge AND my modded TLF 550 biopellet reactor that is a 3/4 tubing to 1/2 which has 2 outlets. 1 tube that flows to the inlet of my skimmer and the other controls flow through my 1/3hp chiller and returns back into the opening of my skimmer . I feel as though the Pump is being pushed beyond what it's capable of handling. So I ordered a Jebao DC 6000 that is coming Wednesday. I like the thought of having a variable speed pump with 6 speeds and a FEED mode with the push of a button as opposed to opening under the tank, closing the ball valve while unintentionally speeding up the flow of my biopellets, chiller and the water forcing into the skimmer inlet. Then having to come back 15-20 min later to adjust the ball valve to get flow back to the tank.