Yellow "Bathtub ring" in Spa

[JeanZ1]

Hi All, I opened my pool this week and although dirty but clear (solid cover), the spa has a yellow bathtub ring around it. It doesn't seem to respond to either the ascorbic acid test or the chlorine puck test. I've had water at SLAM level for a couple of days and notice no difference. I'm at a complete loss of which direction to go. The stain is only in the spa but not the pool. Current chemistry is as follows:

FC= 13.5
CC= 0
pH= 7.8
TA= 50
CH= 320
CYA= 30

 

[mknauss]

Try a magic eraser? Could it be pollen?

 

[JeanZ1]

I don't think it's pollen, but I will definitely try the magic eraser.

 

[Killer95Stang]

I have something similar in my spa. It appears to be pollen embedded in calcium deposits. My spa gets very little movement of water and for some reason, the pollen never makes it out with the overflow of water back into the pool. It comes off with a pumis stick and a little elbow grease.