I have found that with an air conditioner I can avoid a chiller for the tank and keep myself nice and cool in the process. They use a lot of electricity though! I just love my Hydro bill in September LOL.

I'm interested in hearing the impact, if any, on livestock when suddenly confronted with a reverse photo period. I'd guess it's not much of an issue for coral, but wouldn't fish get jet lag or something? Feeding schedule suddenly out of phase? I have a breeding pair of Maroon Clownfish & a sudden shift like that would surely mess with the spawning? Thankfully LED lighting has helped significantly in keeping the temperature down during the day. The old MH/T5HO set up would have caused issues by now. Don't think I'll want or need to switch to a reverse photo period.

So far with open windows at night, closed during day & my DIY LED fixture, the house & tank temperature have been staying in the mid 20s C, that's somewhere around the 80F mark. Looks like forecast calls for extended period in the 30s for Vernon, so I will have to get out the portable AC & fire it up within the next few days I reckon. Usually set if up in the dining room, not far from the tank.