ID stringy white stuff on rocks

[Sidius]

Hello!!

I've noticed some white stringy like stuff that has been growing on the live rock I bought from JL and lately has spread to some of the dry rock I cycled as well. Some of the older strands have slowly turned a brown colour but were white/beige for a long time.

The pic shows some newer growth on a small piece of rock from JL. Is it just a harmless bacteria growth that will subside or could it be the start of some nuisance algae?

It's not all over the place but I do see more of it sprouting up.

I have blue legged and Scarlet hermits but they seem to ignore it. My cerith, astrea and trochus snails seem to ignore it as well. Bio-load is fairly small with just the cleanup crew listed, scarlet shrimp and a purple firefish at this point.

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