Red Slime or Hair Algae or ??????

[ensquire]

Have had this tank running for 4 weeks like this as I decide how to replumb it and all has been good until earlier this week. The tank was acquired from someone that didn't take care of it, and was covered with this same infestation. But when I got it , I took it all down and stored the rock in old water for almost 3 weeks. I set the tank back up a month ago and the rock looked like it was mostly dead, but it had a few good looking pieces that started to revive all the rock, and then this came back.

Water parameters are:
Temp - 28
SG -1.027
NO2 - 0
NO3 -10 mg/l
NH3 -.01 mg/l
KH - 100 mg/l
Ph - 8.4
Phos -1.0














I'm tearing it all down again and adding another feed line maybe a herbie, but should I treat this now , before putting the rock in a rubbermaid with powerheads and heaters ? What is it ?