@RemiHi...some quick notes to your cyno problem...
improve filtration like changing your filter soaks or first filter pads
vacuum the sand and rocks to help remove it
Increase water flow and/or have the flow more random inside the tank
reduce light time and or reduce light intensity, and red/green white spectrum
mgt of PO4 important, either seachem phosphate Phosguard or any gfo.
adding Microbactor 7 very good but have to mgt the dosing...do not just dose a large amount spread it over days...
last resorts are with caution
Chemiclean (I use it once long ago took out some corals)
Erythromycin works good.
Understanding that cyno issues can be from too much nutrients, nitrogen and PO4 so develop some sort of change to your routine.
I hope this helps...
I will revisit this tomorrow,,,,
I have to go bbq...girl is home....
Have a great night......CIAO STALLONE......yes I am a expendable move nut and Rambo...