Struggle to keep water cold

Hello everybody, I'm new to amphibian keeping, I keep tropical fish and decided to get a fire belly newt for a change, I have ran into a problem that I normally wouldn't encounter with tropical fish keeping,

Keeping water COLD

After much reading I know that I want the water temps below 72 degrees to be optimal for the newt, preferably in the 60's, but because we have to keep our house at room temps I am constantly struggling to keep my tank at a decent temp, it normally is around 73 degrees but I want it lower so its healthy for the newt.

If anybody can give me some hints on how to keep water levels down for newts I would really appreciate it!

Oh and also I'm looking for some tank mates for my Japanese fire belly so if anybody is selling fire bellies or is getting ready to then please contact me!

i keep a few gallons of water in the freezer to add to the tank and i also keep ice packs frozen in freezer bags that i'll hang in the tank and the newts have no problem with them

This article should be helpful:
Caudata Culture Articles - Cooling

Good luck!
Heather