No not running carbon.
The string of events were:
I did a water change (while scrubbing rocks of algae), from water I mixed a while back.
I dosed nitrates to 14ppm, from 8ppm. I was trying keep cyano at bay by keeping nitrates a little higher, which has been helping.
And I messed with my lights..
Then they balled up in a day or two. About 4 days later I added 'vite essentials' (I think that's what it's called) which is just trace minerals and elements, for the first time. I've really wanted to see Coraline grow. A year in and many attempts at seeding the tank it just won't spread. I thought maybe the obscure elements may be behind this?? It's a stretch I know..