Brown stuff on rocks

[Ulmo]

hi guys I've been curing some pukani that I got dry for about 7 weeks. I noticed a while back that some brown stuff started spreading on some rock. What is it? I can scrape it off with my nail. Ammonia has been at 0 for about a week now, been treating the phosphate with lanthanum chloride for a couple weeks. Curing in darkness with lid on bin.

https://lh5.googleusercontent.com/PTo_cqbq5NtB7JJLkMDUYF4VuI6erNFVGpzyysyVqb0=s192-p-no

[kien]

Likely a diatom bloom as a result of the curing processes.

[sumpfinfishe]

+1 :wink: