Hello everyone. I have an older 16,000 gallon in ground plaster pool. This year these stains popped up. I thought they were from the neighbors leaves etc from their trees. I super shocked the pool and brushed my heart out. They are still there. Any idea of what I can try next. The appear to be a rust brownish color. Thank you for any insight.
Please help identify stains
- Thread starter VondaP
- Start date
- Jun 22, 2014
- 49,365
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Those look like tanin stains from something falling onto the pol lfloor and moving around (like an acorn or seed of some type). Usually we think of these as organic, but some items have other trace particles. Try either of the following:
- Run a stain with a chlorine tab or sprinkle some cal-hypo on it.
- Try rubbing a stain with a Vitamin C tablet.
Let us know what happens.
- Run a stain with a chlorine tab or sprinkle some cal-hypo on it.
- Try rubbing a stain with a Vitamin C tablet.
Let us know what happens.
Thank you. I have tried Vitamin C, it did nothing. I will have to buy a chlorine tab or cal hypo, I only use liquid. It’s super chlorinated, I’ll have to wait until it is safe to enter. Is there another way to get those in there without getting in the pool?
- Jun 22, 2014
- 49,365
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Very likely they are organic then. Testing with a puck or cal-hypo "should" confirm. If so, then maintaining a consistent/elevated FC level with brushing should help to eliminate them.
I will purchase a puck. I keep my pool CYA at 40 and my FC at 4. I brush often and nothing has made them even a bit lighter.
- Jun 22, 2014
- 49,365
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
I suspect an FC of 4 isn't even close to having an impact. An elevated (SLAM) level of 16 is safe with a CYA of 40 as noted on the FC/CYA Levels. So if the puck (or cal-hypo) test is positive, increasing the FC somewhere between 10-14 may provide better results over time.
- Jun 24, 2021
- 9,081
- Pool Size
- 30000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60
I generally have my FC at 4, I super shocked and currently have it over 20 trying to scrub the stains to no avail. Are you saying to increase to 10-14 for the long term? No fertilizer in the area.
- Jun 22, 2014
- 49,365
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Not quite yet. Try the puck or cal-hypo test first. If either of those work, then you know it's organic and can consider maintaining a slightly elevated FC level for a week or two. But no need to go crazy high over one's appropriate SLAM FC level.
I will try the puck, some of the stains are on the side of the pool, the cal hypo would just slide right down.
Darn it. Puck did nothing. My pool was built in 1988 and has never been replastered. It is rust from the rebar. I’m so sad.
- Jun 22, 2014
- 49,365
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
I would've expected the stain to react with the Vitamin C if it was rust. Seems odd. 
I wonder if you placed a magnet in the area if it would try to stick.
I wonder if you placed a magnet in the area if it would try to stick.I can try that when the chlorine levels come down.I would've expected the stain to react with the Vitamin C if it was rust. Seems odd.
- Jun 22, 2014
- 49,365
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Geez, something really dropped all around your area. I would've bet money in Vegas the Vitamin C would work. If not that, then chlorine for organic. The spots seem too light brown to be copper.
- Jun 24, 2021
- 9,081
- Pool Size
- 30000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60
I do not have anything to fertilize. However, my cameras picked up my neighbors yard guy spraying and using some powder or similar to the tree right by my pool.
- Jun 22, 2014
- 49,365
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Do you happen to have kids at home? We've also seen where some toys can deposit products that can cause staining. Things like BB guns come to mind, but there are other items. Just a thought.
- Jun 22, 2014
- 49,365
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Do you happen to have the bag still around? It would help to know what the ingredients label listed. Or if you know the exact brand of fertilizer, we can try to look-up the SDS online to find the ingredients. Many fertilizers have iron in them which is another reason why the Vitamin C tablet test "should" have worked. I believe some fertilizers may have copper though, so it's best we try to find the ingredients if possible.