Cyano in Breeding Tanlk

I have an established Melanopus pair that are in a 40B with a HOB CPR fuge with a massive amount of Grape Caulerpa in it. The tank has a dinner size plate of cyno growing on the bottom. There is a very small amount of  sand on the bottom, and the female has fanned it all away from the pot. So some is on the glass and the rest is on the sand. Should I
 
A.) Do a 3 day lights out, and risk tossing off their cycle
B.) Use Chemi-Clean
C.) Leave it alone?
 
If I do a partial H2) change, it comes back in a few days. The SG is 1.021. Temp is 83.1, Lights are an AI SOL Blue that is on starting at 0630 with a 1 hour ramp at 0% Whites, 20% Blue and 35% Royal, then at noon the whites come on at 30%, the blues stay the same over an hour,  then at 2130 the lights start a 30 minute decent to 0.
 
I am running a skimmer.
 
Thoughts?