Going to try my first lager (creemore clone-ish) so I built an insulated box to control temps better. For keeping it at the proper temps I used the stainless steel immersion chiller that came with my robobrew to run chilled water from my keezer tap chiller pump. I need a new temp sensor but so far it's keeping temps properly. Fermentation box built and it's holding temp great, granted there was no load on it from the yeast but it should keep up just fine. The ice packs were to help it get down to temp initially and were still mostly frozen 24 hours later. I may have to add them through out the fermentation but not a big deal, time will tell.