From green water to cloudy water

beachhouse

Bronze Supporter
Jul 11, 2021
79
East Hampton, NY
Pool Size
30000
Surface
Plaster
Chlorine
Liquid Chlorine
Hi,

I just opened my pool after the winter and sadly discovered that the water (under the cover) was dark green.
FC was at zero and CYA was < 20.

I SLAMed the pool using Cal-Hypo as I had a 50 lbs leftover from last year, and I need to increase the CH anyway.
I also added Muriatic Acid to bring PH to 7.4 and 3lbs of CYA.

This morning, the water is blue again, but it's very cloudy, especially on the deep side of the pool.

Here are the test results from this morning:
- FC: 7
- PH: 7.4
- CYA still < 20 (I guess it's still dissolving)
- TA: 60
- CH: 250

Is the cloudiness due to the Cal-hypo?
Should I just wait one more day and see if improves?
Or should I keep SLAMing?

Thanks,
Fabio
 
The SLAM Process is a specific procedure with stated end goals, one of which is clear water. It sounds like you simply shocked the pool and let the FC level drift down again.
You're right. I just re-read the SLAM article. The only problem is that with CYA < 20 it is very hard to keep FC at the right level during the day. I'll re-measure my CYA tomorrow morning. Hopefully, it's at 30.
 
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Sorry I didn't post any updates!
After 4 days of SLAMing, the water became crystal clear and I passed the OCLT test. The water has been perfect since then.
I know it's obvious to you, but it was like a little miracle for me.

Thank you again for your help @MITBeta and @Newdude !

My only doubt is that the pool "consumes" around 15 oz of CalHypo / day.
What I mean is that I need to add 15oz of CalHypo / day to keep the FC at the desired level.
My CIA level is at 40.

Can that amount be considered normal?
 
Can that amount be considered normal?
Depends on the % of cal-hypo you are using. The PoolMath APP (Effects of Adding) give you a projected FC increase effect based on the amount and % strength used. You have a good sized pool at 30K, so if it was 73% strength, that's only about 2 ppm of FC which is good. As long as you are not exceeding 4 ppm of FC in a 24 hr period you should be fine.
 
Depends on the % of cal-hypo you are using. The PoolMath APP (Effects of Adding) give you a projected FC increase effect based on the amount and % strength used. You have a good sized pool at 30K, so if it was 73% strength, that's only about 2 ppm of FC which is good. As long as you are not exceeding 4 ppm of FC in a 24 hr period you should be fine.

Good point. I use 65% CalHypo. Basically, my FC drops by 2.6 every 24 hours.
I never realized PoolMath had that feature. It's pretty cool!
 
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