I bought a 1/10 HP Prime mini in-line chiller from fostersmith and it works great. My only concern is the temperature differential. It only kicks on when the water temps go 2 degrees F above the set temperature. What's the logic behind that? Im a bit confused.

Anyways, to put it plainly, the chiller brings the temps down to 73, then after a few hours when the cool wears off and the temps go back up to 75 the chiller kicks on and brings it back down to 73 again. It does this probably a few times over the course of the day maybe more. My question is, will this constant flux in temps pose a threat to my seahorses or any small gobies that i may introduce into the tank? Yes i do have a heater hooked up to the back of the chiller as well and it too is set to 73.

anyone at all?

That's perfectly fine. Mine does that as well. Otherwise you chiller would constantly be kicking on and off if there was only a 1 degree variable.

I would consider setting my heater at 72 for the summer. You don't want it working against your chiller.

I have their 1/3 hp chilling tower. Hold the up & down buttons simultaneously for 8 seconds....then set the temp differential to 00....the factory default is 2 degrees. set it at 00 and there will be no differential.....Mine is set at 79....kicks on JUST as it touches 80.....Never see anything below 79 nor above 80! Great chillers!

The factory default is 2 degrees because it is what is easiet on the equipment while providing a steady environment for the tank. It's really not recommended to set it in such a manner because it is hard on this expensive piece of equipment.