Cyano on my Pukani rock from BRS

That looks Brown to me in that picture.. Not cyno.. I had a Cyno bloom in most of my tanks at the 3-4 month mark

 

How long did you cure the rock from BRS before putting it in your tank?

 

Even dry rock has carbon matter that will decay. The reason for curing is to allow the decay to take place somewhere "other" than your tank. What you are experiencing is the nutrients from the decay feeding the cyano and algae. With you tank lights on, the cyano and algae have everything they need to grow.

If you don't have too many fish, let someone keep them for you, or set up a quarantine, and cure your rock for 4 to 8 weeks.

 

There is another option, you can acid dip the rocks and place them back in the tank, removes phosphate saturated layer and the biologicals.

 

Muratic acid, available at lowes ($7 something a gallon) and menards. It is 28%-30% HCl mix 1 gal acid to 9 gal water (this gives you about a 2.8-3% solution) put the rock in the bucket and let it sit, it will bubble away, eating the top layer and removing biologicals. Here is a pic of my acid dip on my BRS pukani. I soaked for about an hour, which was too long, only need 20-30 mins. I rinsed with water and put it back in the tank, calcium carbonate in the rock neutralizes the acid just like baking soda. I dipped rock this weekend hoses it off and put it straight in a live tank, no ammonia, no harm to my fish, and most important no change in PH
Before dip

During dip

 

Doing an acid bath is a good idea ...BEFORE cycling the rock. But, if your tank is cycled and contains coral and fish...don't put the rock in acid and then put back in the tank. If you put your rock in acid, all the bacteria will be killed...thus, putting back in the tank will cause the tank to cycle once again, only to result in ammonia and nitrite spikes, which will kill your coral and possibly the fish, depending on how hardy. In my opinion, you have 2 options...1) fight through this breakout with lots of water changes and occasional rock scrubbing and limiting the light exposure to bare minimum, and 2) remove all livestock (quarantine, or have someone take them for a season) and cure the rock in a dark place for 4 to 8 weeks.

I did the same thing you did years ago and fought it for a good 2+ years. There are no shortcuts, there is no silver bullet.

 

Here's a good video from Bulk Reef Supply that explains the curing and cycling process...

http://aquarium.bulkreefsupply.com/search?w=how%20to%20cure%20dry%20rock

 

If the cyano gets on the corals, remove it (by gently blowing it off the coral). Cyano can kill corals by smothering them /DesktopModules/ActiveForums/themes/_default//emoticons/sad.gif

 

If you have substrate, it really helps to minimize the spike.

 

Just syphon out the cyano. run gfo,carbon, and do regular water changes. Eventually the phosphates and nitrates will completely leach out of the rock and as long as your parameters are good the cyano will disappear. your best bet is to wait it out any drastic changes will just make it worse. I've been through it myself infact I recently moved a bunch of my rocks around which caused a nitrate spike so the cyano returned in one of my tanks now the nitrate levels are getting back to normal and its disappearing again.

I have learned over the years that my tanks seam to do the best when I leave them alone and don't make any major changes and there is no quick fixes trying to get your parameters back inballance too quickly just makes things worse