I'm going thru this heat wave as we speak. I've never used a chiller, although at a cost. I've resorted to running my lights at night also to a limited degree. But this week ive ran my lights for a few hours in the morning and it's lights out for the rest of the day. I do missing sitting on the couch looking at my DT at night timer. I've also been keeping the sump doors open with fan to keep the air moving. Having lots of evaporation, roughly 10g since Monday. I've been lucky to only loose a couple piece and but has been lucky enough to keep my tank steady@82. I need to rethink my approach for the remainder for the summer. It's only gonna get worst...thinking of drill a hole thru a mini fridge and running some tubes thru and use as a chiller. Beats dropping top dollar on a chiller, since a mini fridge is readily available.