The linked product is a powder, it will work, but....you will be treating the symptoms, not the problem. Cyano
is caused by elevated nutrients and or low waterflow. Usually doing series of waterchanges useing RO
water, siphoning the algae, cutting back on feeding, increasing protien skimming and increasing waterflow will clear it up.
If you decide to use the product...you should still do as mentioned above to prevent it from coming back, also note that it will make your skimmer go batty, I would remove it from the system completely until the meds were completely out of the water.