I have a herpstat 4. It is controlling a 3 tub adult BP rack, a split juvie rack (5 tubs, 2 on one temp and 3 on another), and the UTH under my male Bca's tub. I LOVE it.. But, the downside is that all of your equipment must be close together for it to run everything. (all of mine is along one wall). It ends up being cheaper per channel than buying 4, herpstat 1s, but it's a chunk of change to pay upfront.