The white stuff looks like cotton and when you break it a loose it floats around in the water. It is stuck to the base of my artificial plants and onto the plants itself. I also see some on the caves. When I took a piece out it almost vanished not white anymore as if the water inflates it. What do snail eggs look like? Do crayfish lay eggs or black skirts? Please don't tell me it's either of the two I just may not make it thru the night if that's the case! I can't get good enough pictures to show you what it look like. It is no where else except the places I mentioned.
It is not eggs. Female grayfish keep their eggs under their tails. Black shirts scatter tiny eggs into the substrate and it depends what snails you have, but they won't be furry.
It is possibly bits of food that have landed and gone rotten some filters do not pick up left over food and it is best to syphon this out. Adding your pleco might be a good moveas they willscavange leftover food. Also not over feeding is good, but these might be from the flake you've added to cycle!?!?
What ever it might be, it won't hurt to wipe it off and get it out, then see if it comes back.
I got the same problem as they said when i pull it out it like desinergrates, and i stirred up all the black sand , added 10 gal new dechlored h20, and new filters to only have it come back next day even worse???? now what??????????????