Pife, I have a few thoughts about your cyano.
First, your tank looks rather new. Cyano could well be part of the initial stabilisation of your tank, especially if you started with dead rock. When I first rebooted my tank, prior to starting Reef Actif, I had cyano appear for a couple of weeks as well.
I note from your thread that you're dosing some other supplements as well, notably Coral v and Fish v from Aquaforest. I've personally never noticed anything good from either of those products when using them and have since thrown them away. If you like the brand, I have found Micro E helps in getting rid of cyano. Otherwise, Tropic Marin A- and K+ Elements works as well when dosed in a ratio of higher A and lower K. The theory is that higher manganese to iron ratio causes cyano to get "poisoned". I read this off biggles' thread.
What are your nutrient levels? If you've got low nitrates and higher phosphates, that may be the cause of cyano. Carbon dosing on top of that could make it worse.
I don't think Reef Actif is the cause of your cyano.
