Need some assistance identifying what’s on 2 plugs and some of my rock - just under the one plug They are white and stringy. Don’t seem to respond to touch. I took one plug out and scrubbed it with toothbrush in some tank water, rinsed in another dish of tank water and put back and they reappeared. These were both dipped prior to addition to the tank and have been in DT for more than a month. They only appeared on these 2 plugs and the one rock the one plug is glued to.