Water line won't go away

[juxta]

My pool has a gray line around it right about where the water line is. I've tried cleaning it various ways including a brillo pad and a magic eraser, but aren't seeing any improvement.

Any ideas how I can get this to clear up?

 

[JoyfulNoise]

Have tried some dilute muriatic acid to see if that helps lighten or remove it?

Fiberglass pool surfaces often suffer from calcium staining that is very hard to get rid of. You have to be very careful with abrasive cleaning methods like Brillo pads as they can damage the gelcoat surface on fiberglass and leave behind scratches that then get dirty and hard to clean. Even Magic Erasers are abrasive, just at a much finer level. Abrasive cleaning methods really should be a pool owners last resort.

 

[pabeader]

Crushed vitamin C in a gym sock. Try it. It certainly can't hurt.

 

[juxta]

Thanks both Matt and Bob. The vitamin C sounds easy enough so I'll try that later.

Matt, I did a quick search and it looks like I'd just mix some muriatic acid with water and put in a spray bottle to spray onto the wall then wipe off. Sound about right?

 

[JoyfulNoise]

Thanks both Matt and Bob. The vitamin C sounds easy enough so I'll try that later.

Matt, I did a quick search and it looks like I'd just mix some muriatic acid with water and put in a spray bottle to spray onto the wall then wipe off. Sound about right?

Yup. Start off with a 5:1 (water:MA) dilution as that should be good enough. ALWAYS wear safety glasses even with diluted MA.

 

[tim5055]

Please remember - Always Add Acid to water, and never the reverse.

 

[juxta]

Thanks for both the safety warnings.

I tried a 5:1 ratio today, but it didn't seem to have much, if any, effect. I tried a few different spots and durations (1-5 minutes before brushing it off). Should I try a higher concentration?

Bob, I still need to go out and get vitamin C to try that out. Been distracted by the holidays.

 

[Catanzaro]

I like the Vitamin C approach. I take Vitamin C tablets one at a time and scrub the line with my fingers on the pool steps (mine are plastic and probably not fiberglass). The first time will be time consuming, but after this, you can probably use a general purpose cleaner. Because any spray will drip down as you are vertical, the MA may not sit long enough to remove the stain line.

This works great for me and removes the scum line that builds up on the steps, especially after a heavy rain. Good luck and keep us posted!