valonia sucks! mega -worst-pest-algae ever.
I am also doing routine valonia patrols, painstakingly on every fragrock that I couldn't swap out, when I changed all my LR out
a couple weeks ago. the bubbles just keep appearing, so i'm sure a retarded quantity of spores were released by the raging mass before and I just have to weather the trail off of that.
but, yes, they will die with a good cooking.
The "dark" part is key, as in pitchblack dark, not corner of the basement dark. that crap can live on very very little light, or at least idle until it gets brighter