48 hrs into SLAM and the yellow in my plaster isn't disappearing

dclynds

Well-known member
Apr 29, 2016
79
Houston, TX
Pool Size
17500
Surface
Plaster
Chlorine
Liquid Chlorine
Hi all. I started a SLAM 48+ hours ago because I noticed what I thought was yellow colored algae in various spots around the pool. It doesn't seem to be disappearing and I can't rub it away with my finger with vigorous scrubbing so could these spots be some sort of stain in the plaster? And if so, what causes a yellowish stain like this? Also, these areas are only evident when it is overcast or shady. When the sun is beaming I cannot differentiate these areas from the rest of the plaster (it all looks sparkling blue). I noticed these areas last summer as well but lived with it without attempting a SLAM. Could it be algae living deep in the plaster where brushing and maintaining high FC won't do anything?

Attached a couple pics, but camera doesn't pic up the discolorations very well... so I added arrows.

Also here are my recent log from Pool Math app:

==========================================

Lynds

------------------------------------------

Build Type: Plaster

Volume: 17500 gallons

------------------------------------------

Latest Test Result Summary:

FC: 18.0 (3 hours ago)

CC: 0.0 (2 days ago)

pH: 7.8 (yesterday)

TA: 70 (26 days ago)

CH: 300 (2 months ago)

CYA: 55 (2 days ago)

TEMPERATURE: 76° (3 hours ago)

CSI: -0.01 (3 hours ago)

==========================================

------------------------------------------

Maintenance 04-29-2021 @ 01:35 PM

------------------------------------------

Brushed


------------------------------------------

Chemical Addition 04-29-2021 @ 01:35 PM

------------------------------------------

+ 149 FluidOunces of Bleach


------------------------------------------

Test Results 04-29-2021 @ 01:34 PM

------------------------------------------

Free Chlorine: 18.0

Temperature: 76°F

CSI: -0.01


------------------------------------------

Notes 04-29-2021 @ 07:31 AM

------------------------------------------

Had been adding bleach to get FC to 22 for SLAM. Since FC maintained a good level overnight (21.5), I will bump up to 25.


------------------------------------------

Chemical Addition 04-29-2021 @ 07:31 AM

------------------------------------------

+ 96 FluidOunces of Bleach


------------------------------------------

Test Results 04-29-2021 @ 07:30 AM

------------------------------------------

Free Chlorine: 20.5

CSI: -0.03


------------------------------------------

Chemical Addition 04-28-2021 @ 08:47 PM

------------------------------------------

+ 96 FluidOunces of Bleach


------------------------------------------

Test Results 04-28-2021 @ 08:47 PM

------------------------------------------

Free Chlorine: 17.5

CSI: -0.03


------------------------------------------

Maintenance 04-28-2021 @ 01:01 PM

------------------------------------------

Brushed

Pressure: 17


------------------------------------------

Chemical Addition 04-28-2021 @ 01:01 PM

------------------------------------------

+ 107 FluidOunces of Bleach


------------------------------------------

Test Results 04-28-2021 @ 01:01 PM

------------------------------------------

Free Chlorine: 17.0

Temperature: 75°F

CSI: -0.03


------------------------------------------

Chemical Addition 04-28-2021 @ 07:26 AM

------------------------------------------

+ 96 FluidOunces of Bleach


------------------------------------------

Test Results 04-28-2021 @ 07:24 AM

------------------------------------------

Free Chlorine: 17.5

pH: 7.8

CSI: -0.03


------------------------------------------

Maintenance 04-27-2021 @ 03:58 PM

------------------------------------------

Brushed

Pressure: 17.5


------------------------------------------

Test Results 04-27-2021 @ 03:57 PM

------------------------------------------

Free Chlorine: 21.0

CSI: 0.16


------------------------------------------

Notes 04-27-2021 @ 01:23 PM

------------------------------------------

Started SLAM with CYA 55. added 308 oz bleach to hopefully bring FC from 7.5 to 22.


Need to maintain FC 22 over next several days.


------------------------------------------

Chemical Addition 04-27-2021 @ 01:21 PM

------------------------------------------

+ 308 FluidOunces of Bleach


------------------------------------------

Chemical Addition 04-27-2021 @ 01:11 PM

------------------------------------------

+ 23 FluidOunces of Baume31


------------------------------------------

Test Results 04-27-2021 @ 01:06 PM

------------------------------------------

Free Chlorine: 7.5

Combined Chlorine: 0.0

pH: 8.0

CYA: 55

CSI: 0.16


------------------------------------------

Maintenance 04-27-2021 @ 01:06 PM

------------------------------------------



Pressure: 17.5


------------------------------------------

Notes 04-27-2021 @ 11:57 AM

------------------------------------------

Noticed yellow algae bloom near steps. Poured 64 oz bleach near steps with pump off. May need to SLAM.
 

Attachments

  • 20210429_164822_copy_1612x784.jpg
    20210429_164822_copy_1612x784.jpg
    138.5 KB · Views: 23
  • 20210429_164749_copy_1612x784.jpg
    20210429_164749_copy_1612x784.jpg
    116.7 KB · Views: 23
Thread Status
Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.