What temperature do you recommend to keep the livewell at? I assume 70-80 is a safe range, right? Of course this isn't a huge issue seeing as I change  my water out very often while holding fish but this will help my judgement as to whether or not I'm wasting my battery juice on the aerator(sp) or not.

I pretty much let mine run, you can put on a timer if there is a large amp. draw.  I don't know what the temp. range is but I believe ammonia is something else that can build up in the water, if it isn't circulated.