I sold mine (after 2 years) and bought a Deltec 601S. The maintenance on the Koralin is abusive not to mention clumsy. They didnt think out the physics very well. I had it on my 135G and it wasnt big enough either and kept air locking. The Deltec runs rock solid with A.R.M. but not with the prescribed Rowalith media. I ran the Rowalith till I was blue in the face with my Kh continually dropping every day and could never get a handle on it trying every method available to dial it in. I would say I now am a Deltec fan running ARM.

-John