Yellow stains on return eye balls/fittings.

richmgreen

LifeTime Supporter
May 26, 2010
185
Central Connecticut
Hi. I had yellowish staining on my return eyeballs and fittings. My white fiberglass stairs did not show any staining. Reading the forums, I put the eyeballs in a cup of water with crushed up Vitamin C. Most of the stained cleaned right up which leads me to believe it was iron staining. Pool water was clear and my PH was 7.5, Alkalinity 110, CYA 65, Calcium 150 (vinyl pool). Stayed at these numbers most of the season. My salt generator was left higher for the hot summer, and the Chlorine readings were high for a good month. Free Chlorine 15, CC 0 TC 15. Usually I keep it at about 5-7. Why iron stains and why just through the return eyeballs/fittings? Can I just clean them up or will I need to treat next spring.

Pool is now closed for the winter.

Thanks
Rich
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
32,976
Laughlin, NV
You can see it on those. I get the same thing. Our water is very low in iron but we get large evaporation and no rain. So the iron concentrates.

Just clean them up as you did. You cannot drain your pool so doing a full Ascorbic Acid treatment is not as viable.
 
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mickey4paws

Bronze Supporter
LifeTime Supporter
Apr 10, 2009
725
S.E. MI
Thanks, Marty, we get that too and I never knew what caused it. When we close for the season, I put the returns in a bucket of muriatic acid solution of 4 parts water, 1 part MA, and they come out like brand new.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
32,976
Laughlin, NV
Interesting that MA works for you. I tried that on the spa return covers I can take off. Did nothing. But a handful of Viamin C tablets in a bucket, boom, perfectly white again.
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,855
SW Indiana
The chlorine level is going to be highest in the return plumbing, so that’s where most of the iron will deposit.
 

mickey4paws

Bronze Supporter
LifeTime Supporter
Apr 10, 2009
725
S.E. MI
Interesting that MA works for you. I tried that on the spa return covers I can take off. Did nothing. But a handful of Viamin C tablets in a bucket, boom, perfectly white again.
I wonder if mine isn't iron? Our city's water comes from the Detroit River so who knows what's in there. It's when I take the salt cell off for the winter, I pour the MA solution in it for about 3 or 4 minutes that I throw the returns in. It's strange because we have the same discoloration on the inside of the cell where the plastic is. The MA solution cleans that right up too. I'm debating on not using MA this year if the cell looks ok because I'm reading that MA isn't good for the plates. Maybe I should try Vitamin C on the discoloration and the return eyes this year.