Didn't realize thread became so active. Yes, I know I didn't give all info about how to get rid of it. First if it is a new setup(less than 6mo) it is probably going to happen, just about everyone goes though it. Did not look too awfully bad(yet at least), that is why I didn't suggest using chemicals yet. And, not fimiliar with experiment, but it has help me in the past by shutting off altogether, also found 50/50 bulbs have tendency to not help the situation. If prob is really bad,especially in established tank, I would suggest: remove as much as possible, do water changes, increase flow, reduce feeding to every other day or every third day if possible, change lighting(spectrum,duration,new bulbs), test PO4 levels and bring that down if needed with one of the ferric oxide products on the market, then use Chemi-clean if still needed. I have used it my self sometimes. The stuff(cyano) can be murder sometimes. Also, have found that it tends not to grow on black sand, not that will rid the system, but have seen it help. If using Chemi-clean follow directions, don't overdose, better to use too little than too much. If needed repeat. The stuff works, has not bothered anything(coral,fish,snails,crabs,urchin,shrimp,lobster,cucumbers,featherdusters, etc.) in my tank when I have used it in the past. I think I'm about done here, I guess you could rinse LR with fresh SW too. Use small plastic tools to get stuff out of nook and crannies, helps to blow detritus around every week or so, lets the filter take it out and the corals and other creatures consume it. I don't think I have forgotten anything here, but who knows. I hope this helps with your problem.
Matt