Yesterday, I gave the tank a day of darkness. The cyano was just getting too much, so I decided to give this a try. I had tried it once before, but I chickened out last time and allowed 1 halide to be on while the lights were raised up.
This time, I didn't let any lights come on at all for about 40 hours. During this time, I fed the fish as normal.
What a dramatic difference! The cyano is 100% gone. Now...it remains to be seen if it will come back or not. If nothing else, I have learned how to make the tank look really good for when we have our next BBQ or frag swap, anyway.
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400 gal reef. Established April, 2007. 3 Sequence Dart, RM12-4 skimmer, 2 x OM4Ways, Yellow Tang, Maroon Clown (pair), Blonde Naso Tang, Vlamingi Tang, Foxface Rabbit, Unicorn Tang, 2 Pakistani Butterflies and a few coral gobies
My Tank:
http://www.canreef.com/vbulletin/showthread.php?t=28436