Cyano is eveyones tank, even yours already. Using a chemical on it will not solve anything. I see no cyano. Keep the leather under proper conditions and it will do ok. Changing it between 3 different tanks in a short period does not help either.
Cyano grows as the result of nutrients, stop using chemiclean. It will not solve cyano issues and it stresses out the tank. Chemicals and reef tanks dont mix.
Ive seen people use chemiclean and it wipes out fish etc. only to have the cyano come back at some point shortly after or algae grows in its place. Just trying to give you the headup. Cyano is not an infection that will spread because it is present on a coral it requires nutrients just like algae to grow. If you have no nitrates and no phosphates then you wont have a problem.
If cyano would be present on the coral which i do not see that it is, then simply siphoning off the cyano will be sufficient so as to not inteoduce thise bound nutrients into your tank.