Do I have dead algae

[browerjs]

I opened my pool 2 weeks ago and over the last week I’ve been getting brown spots on the floor of the pool. It also tends to collect at the seams of the vinyl liner.

I will brush it and it dissolves instantly, but just keeps coming back sometimes an hour or two after brushing.

My pool water is perfectly clear except for these spots.

Based on everything I’ve read, I have dead algae, but my FC is staying pretty constant at about 3 with my SWG. My pH is at 7.5, CYA 50, TA 90.

 

[mknauss]

Do an Overnight Chlorine Loss Test
Raise the FC to 10 ppm for the test.

 

[browerjs]

Do an Overnight Chlorine Loss Test
Raise the FC to 10 ppm for the test.

I actually did this last night. Turned off my SWG overnight and it looked like the FC went down about 1, maybe 2 (was 3-4 originally). This morning I dumped a gallon of liquid chlorine in and the FC is over 10. I also turned the SWG back on. Should I do this again tonight?

 

[mknauss]

I actually did this last night. Turned off my SWG overnight and it looked like the FC went down about 1, maybe 2 (was 3-4 originally). This morning I dumped a gallon of liquid chlorine in and the FC is over 10. I also turned the SWG back on. Should I do this again tonight?

From your data, you should follow the SLAM Process

 

[Bperry]

I actually did this last night. Turned off my SWG overnight and it looked like the FC went down about 1, maybe 2 (was 3-4 originally). This morning I dumped a gallon of liquid chlorine in and the FC is over 10. I also turned the SWG back on. Should I do this again tonight?

Realistically I think 3ppm is too low with a CYA of 50, even though the chart says a SWG can do that. If you lose more than 1-2ppm during the day, you’re in danger.

 

[Grendel2000]

This sounds like what I struggled with for years until this year, and I did exactly what you’re doing: SLAM the heck out of it. Still didn’t fix it.

I’ve come around to believing it was pollen FWIW and the only thing that’s successfully dealt with it is my new robot that has extra fine filters (the pleated kind) or repeatedly vacuuming water overboard.

Good luck!

 

[Newdude]

my FC is staying pretty constant at about 3

 

[Mdragger88]

Having the same issue with dead algae… seems to return each day, even after vacuuming. Used the test kit, and as best can tell my FC is 11 ppm, CC is .5, but my CYA test seems way too high… 100+ ?! Added the drops, cloud obscures the black dot, but the level is not even under up to 100?
Must be missing something?

If you’re using trichlor/dichlor for chlorination that’s not surprising. Time to replace most of the water to get the cya down so you can reasonably do the
SLAM Process
Do step 8 to get a better idea of how high the cya actually is.

CYA - Cyanuric Acid Test

Cyanuric acid (CYA) is the chemical name for the product commonly called “pool water stabilizer” … Read more…

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