One thing you should be aware of with the RSR 525XL is that it's overflow is probably going to be the noisiest thing in your system. Every time I think I have mine dialed in, something varies slightly in the return flow, and I'm back to slightly over or under adjusted on the overflow. To make matters worse, the overflow box is asymmetrical. The return comes out on one side of the overflow,and this causes issues if you use an alternating flow on your circulating pumps. I'm using Gyres in anti-sync mode on opposite sides of the tank. When the one on the right side of the tank is cranked in forward, a lot of water is pushed into the overflow box, the water level in the overflow rises, and I can easily end up dumping water into the emergency overflow pipe which can get loud. Once the flow switches and the Gyre on the left is cranked up, the return outflow pipe blocks some of the flow into the overflow box, the water level drops, and if I'm not careful will cause the main overflow to pull air (REALLY Loud). This may not be as big an issue with more traditional circulation pumps, but it definitely is with Gyres. Also, others have noted that the overflow on the RSR 525 is tricky at best (do a search on this site), so I don't think it's solely a Gyre issue. Just wanted you to be aware that this tank is pretty quite overall, but can become a bit noisier than expected if you want to have a lot of alternating flow in your system as I do for SPS.
