When living in Tucson, Arizona, where tap water can be 80F, I would take small plastic bottles and put them in the freezer. Then I can use these dropped straight into a bucket of developer, etc., and cool it off without any dilution. Ice without the melting problem. That was the main method to fine-tune temps. Fridge and time of day would do the preliminary work, getting things close. Washing was done in baths, not running water.