Roger, mine is having a problem, I think. I installed my osmolator with calcium dispenser 2 months ago. I have a 30 gal tank and had been using 2 tsp of kalk each week. I am always careful not to spill any of the powder in the topoff water container so as to avoid any calcification of the pump. In the beginning, the kalk water was cloudy white when entering the tank. I've noticed that over the past month, my Ca levels in the tank have been dropping. I subsequently noted that the "kalk" water being added to the tank has been quite clear, and I believe that the pump is not mixing my kalk adequately. When I manually shake the kalk container, this is resolved. The water flow is still quite strong, so I don't think the pump has malfunctioned. Also, I have not changed my head height at all. Is this a common problem, and can you recommend a fix? Thanks in advance.