Organic staining in spillover spa

Enumjon

Well-known member
Apr 30, 2020
102
Tijeras, NM
Pool Size
25000
Surface
Plaster
Chlorine
Liquid Chlorine
Our pool has had significant stains in the spillover spa since we purchased the home and accompanying pool 2 years ago. I paid very little attention to he spa, since we almost never use it. I assumed that it was mineral staining, but none of the stain testing made any change so I let it be. By the way, the spa is surrounded by piñon pine trees that drop copious needles in the spa.

This year the stains bothered me, so I did the testing again. Still no change. However, this time just to see I left a puck on a stain for an hour or two. When I came back it had cleared out a nice circle, the clean circle being about 2 inches larger than the puck. So my answer is organic stains, but very stubborn stains.

The standard treatment for stains is to hold a puck or vitamin c on the stains. Problem is my stains take 1-2 hours to remove. Much of the spa is covered, including sidewalls, so the time involved would be significant.

Is there a way to make the spa acidic enough to take away the stains? I have a booster pump that only runs the spa and bypasses the heater, so I could keep the spa water away from filter and heater while it does it’s thing.

BD74879A-CD16-4D77-9E8A-57D079CA958A.jpeg
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
18,467
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Did ascorbic acid do anything for the stains?
 

Enumjon

Well-known member
Apr 30, 2020
102
Tijeras, NM
Pool Size
25000
Surface
Plaster
Chlorine
Liquid Chlorine
It did not do anything, but I left it on for 5-10 min. I have not tried it for 1-2 hours like the pucks.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
18,467
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Can you circle in the picture where you placed the puck?