Hello,

Newbie to Pool Forum seeking guidance. I have some iron stains left from nails that were on bottom of pool for 2+ years while pool was closed during home construction project. I saw on forum that vitamin C tablets / ascorbic acid may remove the stains. After rubbing the equivalent of 8 to 10 tablets on stains I saw little change to the dark brown stains perfectly shaped like nails. However, a couple of days later I found brown/yellow powder gathering on the bottom and sides of pool. When I brush the powder that is accumulated in spots bottom and sides of plaster-- the powder dissipates into the pool water and the surface appears clean. The next day the brown spots reappear, and I once again brush off. I have a Hayward DE filter on my 25K gal gunite pool that runs 12 hours per day, but I do not believe that it can filter out this "powder" like substance. I believe the substance is vitamin C residual because I never saw the powder or had problem before trying the Vitamin C, and the Vitamin C tablets are the same orange/brown color as the stains.

Thanks for any thoughts/ help.


FC 2.5
cc 0
TC 2.5
alk 100
cal 140
cya 30
ph 7.2
temp 84 with full sun for 8 hours

25k gal. gunite, with hayward DE filter, 72gals/min, 1hp motor, pump runs 12 hours per day, have been using Chlorine pucks, but starting want to practice BBB