Well the controller works great, but I wouldn't recommend it for a nano with a halide like mine. Maybe if I had a 75 watt halide instead of a 150. But I've got it totally open top now, lamp suspended with a computer fan on it and I still have a hard time keeping it from creeping up to 85 even when the house is 72 degrees.
Of course, how many people have a 150w halide on a 20 hex. It's nutty.
I say one probe is good for up to a 10 gallon nano. After that, it strains. I've got about 15 gallons of water, maybe a little more with the skimmer and filter.
Don't get me wrong, it helps, I definitely noticed when I went a couple weeks recently without it after cracking the mount I made. But I am not satisfied for my setup.
For the money, you can get that 1/3 horsepower Coralvue chiller when it comes out in August. I am thinking about that, so I can have the most rediculus 20 hex setup of all time! *
(Actually I bought this hex used and I think it was quite old, the silicone is coming off like string cheese now, so I doubt I have much time before I will be forced to upgrade. Probably get a 37 cube or try to fix my 75 if I don't move again next year.)
Anyway, it's very cool and works well, but won't work on most tanks unless you add more probes and then it's not cost effective because you could buy a real chiller for that kind of money.
hope that helps,
matt
Coolworks IceProbe Chiller 
