KurtG wrote:

I ordered some more slimline fans, but my temp still swings from 77 to
84 in a day. Is 7 degrees too much?

yes.


I was hoping to wait till next month to buy a chiller, but it seems like
I need to do something sooner.

Two choices-

easiest - simply set the thermostat on your heater to 84. That's high,.
but not dangerously so (I run my tank this hot myself)

OR

Less easy - get a chiller with a dual stage controller.