I bought this about a year ago and it has worked great for about 10-12 batches. I would simply tape a thermometer to the side of the carboy and then switch out frozen water bottles to keep the temp where I wanted. I have upgraded to a mini fridge now and don't have a need for this. It's a great way to control temps without a big investment.
http://www.homebrewing.org/product....m=ProductAds&gclid=CKDJs7vH0b4CFcpcMgodYAYAAQ
$40 OBO. Thanks
http://www.homebrewing.org/product....m=ProductAds&gclid=CKDJs7vH0b4CFcpcMgodYAYAAQ
$40 OBO. Thanks