The only issue I can think of is: How deep will the probe sit in the water if you install it on the minibow lid? With the AC150 I use, the white probe is almost completely submerged, so this probably maximizes cooling. If the probe sits too high on your lid, you might not be cooling as efficiently as you'd like. I'm not familiar with the Minibow though... Matt's point is also valid, and you'd have to situate it in a good flow area to get even cooling, I'd think. With the AC, this is not a problem.
