Levels seem ok, but had a rapid Algae bloom

[jonnio]

Here's where we are at levels wise (6k gallon above ground with salt generator)
FC - 5.5
CC - .5
TA - 80
CH - 325
CYA - 50
Ph - 7.9

I had been fighting high Ph and TA for a couple weeks and were starting to get that under control. I have been unable to tend to the pool this week, but the levels are stable except the TA is down and the Ph is up from where I left it last Sunday. However, in the last three days it went from clear (not quite crystal clear, but not yet what I would call murky) too large sections of green algae all over the bottom.

I am guessing it's SLAM time?
What did I do wrong?

 

[mknauss]

Welcome to the forum!
You will need to follow the SLAM Process
Wrong - nothing. Life got between brushnig/swimming in the pool. With an above ground pool, it seems not mixing it up via a good brushing or swimming seems to lead to algae.
When you see it cloudy is when it is time to act. And brush the pool every few days, if possible. Or better yet, swim in it.
I suggest you read ABC's of Pool Water Chemistry.

 

[HermanTX]

welcome to TFP.
You probably didn't do anything wrong. I think your area has had lots of rain so that can play havoc on your chemistry. All you need is some algae lurking under your ladder and just a drop below the minimum FC you can get a bloom. Not sure how many hours you run your pump but your FC could have dropped when it was off then the SWCG only got it back to right above minimum. Sometimes it just doesn't take much. The only thing I see when look at the FC/CYA Levels is your CYA of 50 is a little low for recommendation using a SWCG. Try to increase that to 60-70 level then keep your FC matched to the CYA level.

I don't think you need to raise CYA right now because that will just cause a higher FC target. With CYA 50 your SLAM target is 20. If you do raise your CYA to 60, then your SLAM target would be FC at 24ppm. Best to use Liquid Chlorine(LC) to get to that level and maintain it with LC until clear. Turn off your SWCG. Just plan to raise CYA after your SLAM.

You will need to drop your pH (7.2 to 7.5) first because test results of pH when FC is >10 are not reliable.

 

[jonnio]

Thanks everyone! SLAMMING it today!