what's your tank temp running at ?

[TheReefGeek]

We can't give exact numbers because it depends on the animals you are keeping, how quickly the swing in temperature happens, and also the accuracy of whatever device you are using to measure temperature could be off by a couple degrees potentially too.

If you are getting anything over 80, and it is a hot day and potentially getting hotter, I would play it safe and throw in a couple of frozen pop bottles. If your tank temp drops too much, your heaters will kick in. And install fans if you haven't already.