- Jul 21, 2013
- 65,360
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Running your ichlor 30 @ 25% for 14 hours a day generates 1.7 ppm/day in 10,000 gallons.
Black stains just keep getting worse
- Thread starter Rich G
- Start date
Thanks for all the help guys
I plan on doing this tonight, just to clarify the instructions. Do I shut off the pump or just the SWG?
I plan on doing this tonight, just to clarify the instructions. Do I shut off the pump or just the SWG?
- May 3, 2014
- 62,708
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Preferably just the SWCG. Does your SWCG have a timer it operates through? How do you ensure the SWCG does not have power to it when the pump is not running?
Rich,
How old is the plaster finish?
When did the dark stain first appear?
Are there other dark discolorations in other parts of the pool?
How old is the plaster finish?
When did the dark stain first appear?
Are there other dark discolorations in other parts of the pool?
Almost three years
First one appeared maybe a year ago and I didn’t think much of it
Discoloration is only one the sunshelf and exit step which both don’t get touched by the auto vacuum... the horizontal and floor surfaces are fine
Copper staining should not be ruled out. The water needs to be tested for copper content. It also might be plaster discoloration, but it is hard to tell from the photo. I doubt it is algae.
Okay update after the overnight FC loss test
02/09/20 7:45 PM
FC 9.2
CC 0.2 (maybe)
PH 7.6
02/10/20 6:45am
FC 9.4
CC 0.2 (maybe)
PH 7.6
I realize there is probably some error in my measurements depending on how clear is clear when checking the FC, each time it could have used maybe one more drop but it was so close I stopped. Either way I would say I passed the overnight FC loss test.
That said, it looks like I need to get some vitamin C tablets and dry acid and do those tests next.
On a side note, on my Facebook page all the pool people are saying phosphates but from what I am reading on this forum and other places that is not the case. On top of that doesn’t phosphates just encourage algae growth so I should have failed my overnight FC test if phosphates were the issue?
Thanks again for all the help
02/09/20 7:45 PM
FC 9.2
CC 0.2 (maybe)
PH 7.6
02/10/20 6:45am
FC 9.4
CC 0.2 (maybe)
PH 7.6
I realize there is probably some error in my measurements depending on how clear is clear when checking the FC, each time it could have used maybe one more drop but it was so close I stopped. Either way I would say I passed the overnight FC loss test.
That said, it looks like I need to get some vitamin C tablets and dry acid and do those tests next.
On a side note, on my Facebook page all the pool people are saying phosphates but from what I am reading on this forum and other places that is not the case. On top of that doesn’t phosphates just encourage algae growth so I should have failed my overnight FC test if phosphates were the issue?
Thanks again for all the help
It's not phosphates. I don't think that it's copper. It might be silver. Have you ever added silver based algaecide?
Only stuff I have ever added
Stabilizer - Amazon.com: Clorox Pool&Spa Chlorine Stabilizer 4 lb: Industrial & Scientific
Calcium - Amazon.com : Pool Mate 1-2825 Calcium Increaser for Swimming Pools, 25-Pound : Garden & Outdoor
Calcium - Amazon.com : Clorox Pool&Spa Calcium Hardness Increaser 5 lb : Garden & Outdoor
There were some granules that the pool store gave me, I wish I kept the bottle but it smelled like pure chlorine granules
The only other stuff I have added has been muriatic acid and salt
yea, I plan on doing that when I get home tonight.. I just hope my wife doesnt mind me raiding her vitamin cabinet
Bad news..
I put vitamin c tablets in a sock, dry acid in a sock and scrubbed with a chlorine tablet and none of them even phased the stain...
I’m almost wondering if it would make sense to just drain some water out and pressure wash the stains
I put vitamin c tablets in a sock, dry acid in a sock and scrubbed with a chlorine tablet and none of them even phased the stain...
I’m almost wondering if it would make sense to just drain some water out and pressure wash the stains
- Jun 22, 2014
- 52,034
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
If the stains are isolated to the steps, you may be able to do that. But it would ideal to know why/how they got there to start with to prevent recurrence. If we rule out iron, dry acid would indicate copper (although doubtful, you never know), last would be organic (algae) ingrained stains. You could lay a tab/puck on the stain for about 5 min if not tried already. I couldn't recall.
forgot to mention I let the puck sit on the stain just like the dry acid and vitamin c before scrubbing... the pool store folks think it’s black algae which is why the black algae remover got rid of the stain last time and that my phosphates are too high which is why it came back...
gonna take a sample to them to test on Saturday
Last edited:
- Jul 17, 2019
- 4,077
- Pool Size
- 13000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Have you read the article on Black algae?
Note the way to test is to scrape off some and smear it on a piece of paper, or something else white. If it is a greenish color, then it is black algae.
www.troublefreepool.com
Note the way to test is to scrape off some and smear it on a piece of paper, or something else white. If it is a greenish color, then it is black algae.
Black Algae
This guide provides a step by step procedure for eliminating black algae in your concrete or gunite pool. Read full post here.
www.troublefreepool.com
Yes, and I can’t scrape any of it off...Have you read the article on Black algae?
Note the way to test is to scrape off some and smear it on a piece of paper, or something else white. If it is a greenish color, then it is black algae.
Black Algae
This guide provides a step by step procedure for eliminating black algae in your concrete or gunite pool. Read full post here.
I took an underwater video of the stain
- Jul 17, 2019
- 4,077
- Pool Size
- 13000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
I re-read your entire post, and your very first post caught my eye. So you sprinkled something on the spots from the pool store, and they went away for a few weeks. Do you know what this "something" was?
Clearly that pool store stuff isnt a long term solution, but the stain reacted to it. Find out whatever the pool store stuff is, and it will help the experts here identify the true problem and help you fix it.
I plan on stopping in Saturday to see if they still have it.. I will report back