Robot cleaner discoloring, something in the water?

[threecheese]

Hi,

I have a white Polaris robot, I just removed it from the pool and it looks to be yellowing; I wiped it and the yellowing came off! It is a light brown ... substance? I've noticed some staining on the vinyl, but it didnt brush off and survived several shocks so I figured I the winter leaves ruined it and I was out of luck.

Any clue what this could be? And how I might get rid of it? I've been swimming and everything seemed fine, all my levels are right (CYA, pH, TA, Ca) and the water seems mostly clear.

Thank you!

 

[JohnT]

Iron would seem to be the likely candidate. Put a vitamin C tablet on a section of stained liner for a few minutes and see what happens. If it lightens the staining, you may want to consider an Ascorbic Acid Treatment as described in this post Ascorbic Treatment to rid Pool of metal stains. Don’t ignore the part about sequestering agent.

 

[Oly]

Any oak trees near your pool?

 

[threecheese]

Any oak trees near your pool?

Tons. This summer it was filled with 4 contractor bags of leaves that somehow snuck through the cover.

 

[Oly]

Tannin staining from oak leaves is likely your issue. Try a 50/50 mix of chlorine and water to clean your bot. Chlorine should reduce the stains on your liner but getting too aggressive may damage the vinyl so go easy.

 

[threecheese]

Thank you. After opening (about a month ago) I kept is at SLAM for over a week, shouldn't that have killed anything organic? Should I shock again?

 

[Oly]

Tannins are biomolecules found in many plants including oaks and will stain surfaces if not removed right away but they are not living organisms. Chlorine will oxidize, "bleach" the stain but may also damage your vinyl liner at high concentrations. Wait 30 days before attempting to clean your liner as safely chlorinated pool water may resolve your issue. Best to clear oak leaves out of your pool ASAP if you cant keep them out all together.

 

[threecheese]

Appreciate your help. I see your pool is "surrounded by an urban forest", like me (well, suburban ...)! It sounds nice, and it looks very nice, but there's so much debris!

 

[Oly]

Yes pools can collect so much organic debris and windy days make things worse. Your cover should help but I found the fine mesh type not much help. An auto cover above the pool surface would be best but not an inexpensive solution.

 

[DorsalSpine]

Even a solar cover will keep a lot of debris out of the pool. I used one for years before we went to the auto cover.