I keep my halides on for around 10 and the actinics come on an hour before and go off an hour after. Ideally, if I had the space, I'd have 10k compacts as well and only run the halides 8 hours, have the actics come on 2 hours before, the 10ks 1 hour before, the 10ks go off one hour after and the actinics 2 hours after. IMO, this would serve mainly a function of electrical savings and appearance and probably would not affect coral health that much.