Adacaro..kudos my friend, its best policy to not dose what your not testing for. That is, if you dose and can not test it, how do you know your not causing problem. Excellent plan! As for the Cyano
, if your tank is only 3 months, a little more info is needed. Corals, fish, clean up crew, live sand, crushed coral, etc. What kindof lights are they? NO
,etc? Is it in direct sunlight? Basically, its helpful to have a profile of your tank and equipment your using, specifically. However, as others have mentioned, you need to check for any levels of 'unwanted' trace elements as thy can feed the bad algea.