Mottling or a touch of brown algae

[Johnvalliere]

Please scroll down for update.

Hello,
I joined the pool world and forum last July when we bought our house w/pool (see sig for details). We had it replastered, which took from July - October because of the high water table. Since completion in October, I brush and check the levels every Friday. The readings are pretty consistent:

CL 2ppm with SWG set @20% in off season
PH 7.8 (I add 1-2pts each week)probably still normal b/c replaster?
ALK 80ppm
CH 300
SALT 2900 - 3200ppm

I'm just now noticing the slightest trace of brown on the bottom, so I set the SWG to super chlorinate. I then ordered a Taylor K2005C so I can test more thoroughly & accurately. I feel confident that I'm applying the basic advice I've picked up on TFP, but I'm open to any additional insight anyone wants to provide as I move forward with this possible algae issue. Perhaps someone with more experience might see something in my numbers or strategy that needs adjustment.

 

[mknauss]

Just to confirm, did you get a K2005 or K2006 test kit? The K2006 comes with the FAS-DPD test for FC/CC.

What is your CYA?

 

[Johnvalliere]

Hi,

I got the 2005, but your question has me second guessing that choice. My current kit doesn't have a test for CYA, which is what pushed me to order a more complete kit.

 

[mknauss]

You will need a FAS-DPD kit to follow the SLAM Process

 

[Johnvalliere]

I initially thought I had a light dusting of algae, but as I've researched more, I'm wondering if it is mottling in the new plaster. It's too light to capture in photos, but I will post updates as I look into it a little more in hopes that this thread might help someone else.

 

[Johnvalliere]

UPDATE:
The contractor who resurfaced our pool back in October sent someone out to look at the "algae" and he confirmed that it is not algae at all. It is very light mottling. The brownish sandy stuff at the bottom is definitely dirt/pollen. I hope this helps someone else out there. For what it's worth, the scare prompted us to upgrade out test kit AND we'll be testing twice per week. This close call has us convinced that prevention is worth it!