I'm not clear on your 'tub' description ... if soil, your temps in the 80s will be OK (nice if it was a bit cooler, but 80s ain't too bad) ... if it's a hydroponic 'tub', it's a bit too warm (try for 70-75), but not enough to justify a high-dollar 'cooler setup' ... hope that helps, good growing :thumbsup: