Well, my water was getting sickly in the spa. Chemistry was fairly well maintained for 4 months. That and never having done a deep clean, time to do it. Ordered Ahh-some online and it arrived just in time today.
Drained the tub last night, refilled this morning then added Ahh-some and followed the directions.
Lots of bubbles
After draining and scrubbing scum that Ahh-some knocked loose, refilling now. Looking like a new tub!