Since my chest freezer was recently converted to a keezer, I was looking for a new way to control my fermentation temps in my 7.5 gallon Anvil fermenter. I pulled the trigger on their cooling kit and so far it is working well. I put the pump in a 16qt coleman ice chest, filled with water to a few inches above the pump intake, and then dropped in a few frozen water bottles. I was initially concerned with the thermowell's proximity to the cooling coil, but then I figured any cold spots would quickly equalize in that volume of liquid, especially with the churning of an active fermentation.
I've had no issues maintaining fermentation temps. I've been rotating the water bottles every 12 hours and popping the melted ones back in the freezer. There was one night that I forgot to rotate them, and it went for 24 hrs without being changed. The water temp rose and the pump was running constantly to cool the fermenter. The fermentation temperature did not spike too high, only rising to about 2°F above my set point (still well within optimum range for the yeast), but the still somewhat cool water was no longer effective at actually lowering the temperature after 24 hours without swapping the ice bottles. This was at ale temps, holding 65°F during primary fermentation with a 75°F room temp. I have not attempted to lager with it...yet.
The real test will be crashing before I keg this batch sometime next week. I'll probably leave just enough water to submerge the pump intake, and fill the ice chest up to the brim with ice and see what it can do. I will report back with results.
Initial impressions: I like it, it works, though swapping water bottles is a bit of a pain in the butt. I've set reminders on my phone so I don't forget again. If I had a kegerator with a freezer compartment, I would be tempted to set up a simple glycol chiller like in the video above. It would offer a much more hands-off solution, and the lower temps should make it easier to lager or crash.