Depends on how hot your tank runs. Personally, i have a $40 stanley blower fan hooked to a temp controller, Havet' had the temp go a single degree above where it comes on at over the last summer.
My calcium reactor, I'm not letting anyone pry it off the tank. Before putting it, i was doing ph dance with buffers or kalk nightly, and haven't touched since.
Ca reactor takes a lot of work out of the tank, but a chiller will keep things cool if you have a problem with temps and heat fluctuations will kill. ok, thread ressurrected