I will definitely be watching to see the end results with these two tanks. Under the microscope is really interesting but gross. But now I need to know what those worm like things are!
Definitely looks like 2 types of Dino’s. I definitely see osteoporosis and the other kind you would use silicate to get rid of. Fight the osteoporosis first as they are the most toxic.
I've had that same issue with a tank that started with old live rock, but the problem stemmed from a hitchhiker tulip snail in there ever since day one. They always had dead snails and I couldn't figure it out till the other day i was servicing it.