Just found this today as I'm gearing up for growing season. Here in Albuquerque I have two problems during the summer. Heat and wind. I've implemented the "swamp cooler" approach, but didn't have my
nutrient feed & return lines well insulated last year.
One trick that I've been using that I haven't seen mentioned: Instead of 5-gallon buckets with wrapped insulation, I've taken to using 5 gallon drink coolers (because they're pre-insulated.) I remove the spigot and use that as the port for my return lines.