Ice packs to chill tank in summer?

[Coasting]

I use dollar store plastic ice packs....
Largest size of cryowhatever was $1 and is easier to get family to use in the tanks. They poopooed the water bottle idea but then again some people lack common sense in some areas.... anyway works well so far. Been using that brand for a few years as i beat them up for work and travel and dropping on cement and everything else and no leaks.