Having done a lot of math, and checked out a lot of units, I'd like to add my two cents; Having gone through the process of designing and engineering my own cooling plant, plus building out a water cooled system, I can honestly say that it's the best application for cooling indoor gardens, for several reasons:
1. You will have a LOT more trouble trying to route cold air around where you want it than you will with water. Two hoses, an Iceflow box and fan, DONE. That cools up to four vented hoods... in other words, plenty.
2. Cooling with water is more efficient than air. Less thermal mass in the air means less efficiency, period. This goes double when working in dry climates or with dry winter air, and TRIPLE for high altitude applications. IMHO, no one in Colorado should be touching AC with a 10 pole... for anything.
3. I've never seen an AC unit that will chill water for hydro systems. Ever.
4. Water cooling, like AC, can be set up to effectively deal with humidity issues. It's easy, really easy.
5. If you plan to expand, then getting another water chiller usually isn't necessary. If your chiller is up to the job of running one bloom room and the rest of your setup (veg room, hydro systems, etc), then build another bloom room on the flip, and Voila!- you've just doubled your growing capacity without having to buy more cooling.
6. All the freon is contained within the chiller unit; you NEVER need to get involved with it unless you break your chiller.
7. Running an outside water cooling circuit to help save power, and/or putting your chiller inside for the winter to help heat your home are very real, indeed easy to implement options for chillers, but NOT with AC.
I know the current conventional wisdom says 'minisplits are where it's at!', but having done the math and done the build, I have to say that chillers are just plain better. FWIW
