Picking up a one year old tub this weekend. It has sat for a while. It's got a bunch of biofilm flakes floating in it.
When I bring it home I plan on doing the procedures I've read here regarding shocking the tub. I also have ordered some "Spa Purge".
Do I have to drain the tub after the "spa purge process" and before I shock? Or can I do the Spa Purge process, then shock, then drain? I'd like to avoid having to drain twice.