Need help to determine a yellow / brownish spot

[davisito45]

Hi,

I have had a yellow / brownish spot near my main drain in my pool. The spot has been there for about two years before I knew about TFP. I did not think much of it in the past since I did overnight loss test and only lost about 0.5 on my FC.

What is the best way to determine what kind of spot I have? Sorry I did not include pictures but as soon as possible I can post. I have had proper FC levels for the past two years. Could it be mustard algae and what does it look like?


FC 20.0 (currently shocking pool)
PH 7.6
TA 80
CH 420
CYA 40

Any help is appreciated.

Dave

 

[JasonLion]

Try putting a vitamin C tablet on the spot for 30 seconds to a minute and see what happens. If it is an iron stain, it should vanish, or lighten significantly, where the vitamin C tablet was.

 

[davisito45]

Ok, I will place vitamin C tablet and see what happens. It is in the deep end about 7 ft any recommendations on which kind of tablets or it does not matter?

Thanks,

Dave

 

[Butterfly]

Cheap Vitimin C. - the cheap tabs don't have a protected coating that takes time to dissolve.
Since it is that far down, you might want to crush some in a sock and use a pole to hold it on the stain for a minute or so.

 

[davisito45]

Update! Re: Need help to determine a yellow / brownish spot

Hi everyone,

Just an update. I placed some vitamin C tablets in a sock and held it on the spot and it faded away. Problem solved! Actually my wife bought the Vitamin C at Dollar Tree for $1.00 and it has 30 tablets.

Thanks for all of your help!!

Dave

 

[Butterfly]