Both are nice, I am sentimental about the 9205 as the 233 was its great grand daddy and that was the first Tunze product I ever owned, I bought it in 1996 from JP Burleson. I would go with the 9205, provided you can build a partition in the sump to keep the proper water level. The 9005 is a bit easier as it can't run dry so easily but it must be submerged much deeper.