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

[ensquire]

Sand is all new because tank originally was bare bottom, was not a fan of that look.
The rock was stored in buckets , they were only supposed to be there for a few hours but plumbing needed an overhaul. was there for 3 weeks as I waited for plumbing fittings Etc, so probably killed anything good. Have to tear it all apart again and install a overflow box, is it worth dealing with first or just wait and deal with it later? I will clean up rock and store it properly this time. Would hooking a Fluval up full of carbon be a good idea ?