My actinics go on at 830a, off at 10p.
Halides on at 2p, off at 9p.
As far as the usefulness of various photoperiods, you have to consider intensity as well as time. I have seen studies using photoperiods from 10-15 hours, and the effects on coral growth very much depended on intensity. Keep in mind that fish and corals live with a 12 hour photoperiod in the tropics.
To be un-diplomatic for a moment, I find the loose talk about photoperiod and algae blooms to be a bit disturbing. I would be a lot more comfortable if someone were to point to a systematic study showing the effects of photoperiod on algae growth in reef tanks.
Jacobus, your setup sounds fine. If your daytime is their night time, that should work. It may be hard on the animals if they ever have to get jobs on the outside. pH normally drops at night, due to decreased photosynthesis, although it's kind of surprising, since your lights are on at night. Even with a reverse photoperiod in the refugium, mine varies by about 0.2 over the course of the day.
The fern-like thing is hopefully a macroalga that will be decorative and healthy. It may be bryposis, which is not so desirable, but we'll have to see what it starts to look like.
. I wanted to post and just mention that someone had told me what I was doing might not work because I didn't want Mooch to follow what I was doing and then end up with problems. The person who told me I'd end up with a HA bloom was speaking from their own personal experience, they had nothing else to back them up. Apparantly they had a setup 'just like yours (mine), Caulerpa and everything' and zero N and P but HA moved in and took over. Thinking about it now, it's silly to think that an extra two hours of light could be the sole cause, obviously there were nutrients coming from somewhere.
