First things first, be absolutely sure that your tank water is at 1.026. I've seen a lot of !!!!! reactions to alk and Ca tests, only to find out that the tank's specific gravity was more like 1.029 or even 1.030 because of uncalibrated or miscalibrated refractometers.
Secondly, and others noted, it's a heck of a lot easier to switch to a salt mix that is more in line with your desired levels than it is to lower a really "enriched" salt mix. To do that, you have to either time it correctly as the alkalinity and calcium combine in heated, circulating seawater and fall out of solution, or do very small water changes to avoid changing the tank water too much.
About cyano - you've a new tank, and it's normal. I've never set up a tank without going through at least a minor cyanobacteria phase, and I've never heard of someone else doing it, either. And most of those tanks were setup with actual live rock, not dead rock. Yes, you can nuke it with erythromycin (that's what "chemiclean" is), but I hesitate to recommend treating a tank with an antibiotic when it's just getting the bacterial biofilter established. And once the erythro is out of the system, the cyano is likely to come back. The best way to deal with it is just to practice good overall management techniques and wait it out.
