Darkening of pool floor-deep end

krista.l.adams17

Active member
Aug 17, 2024
30
Pearland, TX
Hello!
We bought a home in August with a pool, so I’ve had it for a while but this will be our first full pool season. I’ve got the chemistry part down, but something that bothers me is that the deep end of our pool, like the deepest part, the floor has darkening that the rest does not. It’s not just that it’s deeper. I read somewhere to put a chlorine puck on the area, leave it for a while and see if that lightens it. It did! In fact it looks in that spot just like it should! But the problem is, I don’t know what that means or how to now fix that entire portion of the pool since I can’t very well move a puck around that entire area. Help please :)
 
If pucks lift the stains they are organic.

 
Here’s some photos! I’ll say the photos do make it look darker than it is, but you get my point. I also took some so you guys could see the places where I’ve let the puck sit as well!
 

Attachments

  • IMG_1614.jpeg
    IMG_1614.jpeg
    365.4 KB · Views: 31
  • IMG_1615.jpeg
    IMG_1615.jpeg
    449.6 KB · Views: 31

 

Enjoying this content?

Support TFP with a donation.

Give Support
I thought if the puck lifted the stain it was basically guaranteed to be organic staining not metal. Is this incorrect?
If we believe those test results you have no chlorine in the water so algae would be a likely candidate. You probably didn’t need to raise the alkalinity as pool stores report an adjusted alkalinity to sell you junk you don’t need. Would recommend you don’t trust any of their testing and get your own test kit.

See here:
 
If we believe those test results you have no chlorine in the water so algae would be a likely candidate. You probably didn’t need to raise the alkalinity as pool stores report an adjusted alkalinity to sell you junk you don’t need. Would recommend you don’t trust any of their testing and get your own test kit.

See here:
I do have the Taylor test kit and I got similar results yesterday. Also, I feel like the low chlorine would make sense to me if it wasn’t for the fact that this staining has existed since we bought the home in August. I’m just not sure how to remove it from here, which is why I consulted this group. Thanks for taking the time to respond.
 
I do have the Taylor test kit and I got similar results yesterday. Also, I feel like the low chlorine would make sense to me if it wasn’t for the fact that this staining has existed since we bought the home in August. I’m just not sure how to remove it from here, which is why I consulted this group. Thanks for taking the time to respond.
Post up results from your test kit.
 
You can try to scrape some off to see if it is black algae, but I am 99.999% sure that it is copper.

Black algae is a type of black mold that can be scraped off and examined.

Black algae is a blue-green color and it is a type of cyanobacteria.
 
Trichlor pucks are acidic. They significantly lower pH in their local area as they dissolve. It’s low enough to etch and remove plaster. So while a puck can lighten an organic stain, it can also remove a small amount of the plaster as well and lift a metal stain. So it’s really not determinative in differentiating metal staining from organic staining. An organic stain will lighten almost immediately from exposure to chlorine. If the chlorine source has to sit there a long time with little or no effect, then it’s not organic.
 
Trichlor pucks are acidic. They significantly lower pH in their local area as they dissolve. It’s low enough to etch and remove plaster. So while a puck can lighten an organic stain, it can also remove a small amount of the plaster as well and lift a metal stain. So it’s really not determinative in differentiating metal staining from organic staining. An organic stain will lighten almost immediately from exposure to chlorine. If the chlorine source has to sit there a long time with little or no effect, then it’s not organic.
Okay I understand what you’re saying! So how does one go about removing this metal staining?
 

Enjoying this content?

Support TFP with a donation.

Give Support