The dual Rancos don't regulate 2 separate heating devices, they just provide a back-up unit in case one goes bad ... Rancos have to fail safe to "turn off" if they go bad, so a single unit can potentially cook your collection ... that's why people started selling the "dual units".

If you can't afford a Helix, then Rancos are better than nothing, but when you're ready to run with the big dogs, save up for that Helix!

-adam