Hi hopefully someone can identify this for me. I’ve never seen anything like this before. I tried to manually remove it but it’s surprisingly VERY hard to scrape off even with a toothbrush. It’s a 6month old system 125 gal with a VERY LIGHT bio load(two clowns, a gramma, softies and hammers)...
I pulled some rock out of my poly tank to make smaller pieces etc. Got to this rock and have no idea what I'm looking at? Little white sacks or something? No clue, TIA!