Little Brown Dots

[RedHook]

I have these little brown dots on the bottom of my pool. Any idea what they are? Maybe tannin stains? We get a lot of leaves dropping in the pool, but the Kreepy Krauly runs every day, so none of them stay very long. Most of them are in pairs, about as far apart as the width of my thumb. Thanks!

FC: 10.5
CC: 0
pH: 7.2
TA: 150 (150 is where it stays red, 110 is where it starts turning red. Which is the right one?)
CH: 320
CYA: 90

(edited with test results)

 

[257WbyMag]

Probably organic staining (tannins) from tree debris getting into the pool. Berries and pollen pods do that to mine all the time. Hate those wax myrtles. :grrrr:

On the TA, once you end up with red that no longer changes, that is your endpoint.

 

[duraleigh]

With your CYA that high, I would hold FC up so it never goes below 10ppm. If the stains are organic, they will fade and disappear due to the elevated FC levels.