Couple years ago I tried the ice pack idea when my FW tank hit 85-87 ...
Didn't help, just melted the ice
I went through 2 bags of ice and 1/2 dozen ice packs, to no avail
I ended up buying a chiller
Glad to hear it's working for you
If you have a controller, program it to start turning lights off @ diff temps
Inexpensive 120mm computer fans and a 12v powersupply work well