There is a HUGE thread about this on RC, but it doesn't really have much good info. Here is what I do...
1) I use a toothbrush & baster to get any cyano, film, etc nasties afloat, any hair algae loosened, and the detritus moving into the water column. I try to do this at least weekly anyway, but before the blackout is good especially for algae. I also wipe the glass etc to get the algae off & moving to come out in the overflow/filtersock.
2) Use a piece of window blind, the rollout kind, to cover the entire tank, or as much as possible. I use the big paper clip type binders to hold it to the top edge. Cardboard would be better, as it is more opaque, but I had this available and it works ok.
3)I continue lighting the fuge, for no reason other than I didn't change my controller settings. I dont' think there would be big pH swings of you kept it off, probably doesnt' matter much at all, though you'd get rid of cyano in your sump/fuge if off.
4) I keep lights off for 3 full days. I take the light shield off the last night so the tank gets the daylight from the house/windows before my lights come on at noon.
What have I noticed?
•The water is crystal clear after the blackout.
•After a day of getting light again,
polyp extension is greater.
•Algae/detritus is dealt a pretty good blow
•Cyano &
film algae are pretty much gone
I have not noted any long/short term issues with corals, though I dont' have a ton of acros, acans, etc. Even my clam does fine and has not complained. Things to retract dramatically during the lights-out period, but they rebound well.
I do feed the fish normally, they don't stress out visibly.
I have taken this opportunity to introduce new fish to the system, usually putting them in on the last day so they can figure things out and the existing residents accept them with the new light.
I have done this four times in the last eight months, at no regular intervals.
I hope this helps, let me know if you have any questions, comments, or suggestions.
Matt
