This is a thread I found that pretty much raps up what I have found that hobbyists have to say about using different products in our reef systems. Certainly in many cases there can be extenuating circumstances. Bob Fenner's concluding remarks did not help much either:
http://www.wetwebmedia.com/maralgcidefaqs.htm
There does not seem to be a product available that will knock the cyano out completely, probably due to their cyst stage, IMHO.
Cyano seems to be a major problem for hobbyists, probably greater than algae type problems.
I don't believe any of the products including Erythromycin, are without definite risks.
