Well from what the Tunze web site shows they only really have an alarm type system to monitor water levels in the sump and tank, it is not real clear if it actually will turn on a pump and then turn that pump back off when done filling the sump. And the suggested retail price on the website was $161.00. yes it has three sensors on it one that will detect low water level in the sump, one that will detect high water in the sump, and the other they showed in the diagram was monitoring the level in the tank, basically a high water level alarm for the tank, but if you have a reef ready tank what would you need this for. Plus like I said it is not clear at all if it will even turn a pump on and off to be used as a level controller.
Now as far as the Reeffanatic unit is concerned I know when I tried to order one they were out of stock and had to have them email me when it was available, this tells me quite a few people must be getting these units or they were not producing that many. I prefer to think the latter as they are a Reef Central sponser and you see nothing but good reviews on their units there. Just my .02 pennies.