Fertilizer Stains in Pool

J4CKBOLT

Well-known member
May 22, 2016
108
Friendswood/TX
#1
I swam in the pool this weekend for the first time this season. Swimming with brush in hand to get those hard to reach places [emoji3]. I noticed on the steps in one area I had maybe 20 copper colored stains the size of peas from fertilizer. The brush did nothing to remove the stains. Does anyone have a recommendation to remove set in fertilizer stains from plaster pool surface? Preference not to partially drain pool but I guess I could...maybe muriatic or CLR?
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
14,703
Tucson, AZ
#2
Did you try vitamin C (ascorbic acid) on it? Most fertilizer blends have iron compounds in them as a micronutrient.

Oh, and why are you putting fertilizer in your pool....TFP doesn’t recommend you do that :laughblue:
 
OP
OP
J4CKBOLT

J4CKBOLT

Well-known member
May 22, 2016
108
Friendswood/TX
#3
Did you try vitamin C (ascorbic acid) on it? Most fertilizer blends have iron compounds in them as a micronutrient.

Oh, and why are you putting fertilizer in your pool....TFP doesn’t recommend you do that :laughblue:
Lol thanks for the tip and laugh. I am sure the discoloration is from iron in the fertilizer I used. Ascorrbic acid...something I can get from Home Depot, liquid?
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
14,703
Tucson, AZ
#4
CVS or Walgreens or grocery store - Vitamin C tablets (1000mg per tablet....skip the rose hip flavored one ;) ). Crush up a bunch, put it in a nylon and let it sit on the spot. If it’s iron, it will lighten up.