Confused on what to do

[pixiexkp]

My pool has been running and clear for the past few weeks. The other night I noticed it was cloudy, added extra bleach to bump the chlorine up to 6, cleaned the cartridge filter and ran the pump for 24 hours. Pool was no longer cloudy. This morning, I noticed what I think is some algae starting around the edge of the floor and steps. It was yellow in color. Vacuumed the pool, cleaned filter and brought chlorine up to shock level of 12. The water is still clear.
I checked the water last night
FC 5
CC 0
pH 7.5
TA 90
Ch 170
CYA 30
This morning prior to adding more bleach
FC 4.5
CC 0
Could it be something else? It's easily brushed away.

 

[Richard320]

Two things consume FC" sunlight and organics (including algae)

You lost a whole bunch of FC overnight and you can't blame it on the sun. So it's organics. You see algae and you see cloudy water.

You've started the solution already -- you boosted FC to 12. Do it again and again and again until you pass the three tests. And continue brushing every inch of the pool. The three tests are defined in SLAM Process

 

[pixiexkp]

FC .5 is too much to lose overnight? I thought it was 1 or more meant algae. Pool is clear and CC is 0

 

[Richard320]

FC .5 is too much to lose overnight? I thought it was 1 or more meant algae. Pool is clear and CC is 0

Oops, my mistake. I thought it was 12 last night

So you've passed the overnight loss test. And the CC is less than .5. But you still see algae when you brush, so the advice stays the same even though I was wrong about one part of it.

 

[bmoreswim]

I think Richard misread. He thought the 12 FC you mentioned was earlier, not after those test results. But still on track.

A .5 FC loss on the OCLT is OK if all other things are good. You stated that you had visible algae. That alone is reason to SLAM. That wispy stiff is dead algae which still needs filtering. I would proceed with a SLAM though it will likely be brief since you appear to have caught it early. Don't forget to drop pH to 7.2 before beginning, pump running 24/7, brushing multiple times per day and testing every few hours and re-dosing. The pH test isn't accurate above 10. There are other details I'm he article but I wanted to highlight those.

The real key here is that you had algae outbreak and never raised FC to SLAM level until today. That 6 wasn't sufficient. It only knocked it back and you will likely have a reoccurrence unless you SLAM. As I mentioned, you are practically there but a short SLAM will seal the deal all else being in line.