Cloudy after rain, lowered ph too much?

capricatunes

Bronze Supporter
Jun 3, 2020
26
Minneapolis
Test results before big rain yesterday:

Ph: 7.8
FC: 4

latest other numbers from four days ago:

TA: 120
CYA: 40
CC: 0

I had my pump off for ~16 hours during the storm. Lots of lightning and a bit of flooding (I was told to turn off equipment during that. Yes/no?).

I awoke this morning to slightly cloudy water. Not bad, but not crystal. I backwashed and wasted about 2 inches. The pool wasn’t overflowing, but water was very high. Big winds blowing water (but not much debris) into the pool, and likely some runoff from the cement patio.

FC was still roughly 4 after the rainfall. Ph was 8. I added some bleach.

Then tested today:
FC: 5.5
CC: .5
Ph: 8
TA: 110
CH: 125
CYA: 30

I then added muriatic acid. Ph is now 7.2.

1) should I SLAM?
2) Did I overdo it on the muriatic acid? Should I aerate? Increase manually? Or, can I let it creep (it usually does a bit)? Vinyl liner.

Thank you!!
 

ActivFam

Active member
Jun 30, 2018
30
Minneapolis, MN
Thanks for posting this question. Came here to find answers about slight cloudiness after rain (also in Minneapolis area). We got 5 inches and my pool was slightly cloudy yesterday afternoon.
FC was 4 on Sunday afternoon.
Test results Monday afternoon:
FC 2
CC 0
ALK 110
PH 7.5
CYA last week 30
I was thinking perhaps my FC got too low for too long. Bumped FC yesterday to 5 and doing OCLT this am. I'm on the lookout for algae today. I would've bumped up FC if I knew it was going to rain that much, shoot! Hopefully our pools just need more time to filter. (I cleaned ours yesterday).
 
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capricatunes

Bronze Supporter
Jun 3, 2020
26
Minneapolis
Thanks for posting this question. Came here to find answers about slight cloudiness after rain (also in Minneapolis area). We got 5 inches and my pool was slightly cloudy yesterday afternoon.
FC was 4 on Sunday afternoon.
Test results Monday afternoon:
FC 2
CC 0
ALK 110
PH 7.5
CYA last week 30
I was thinking perhaps my FC got too low for too long. Bumped FC yesterday to 5 and doing OCLT this am. I'm on the lookout for algae today. I would've bumped up FC if I knew it was going to rain that much, shoot! Hopefully our pools just need more time to filter. (I cleaned ours yesterday).
Oh nice! Lmk what you find on the OCLT. I’ll do the same. It won’t be a perfect OCLT because my last measurement last night was at 5:45pm. But we will see.

That rain was crazy.

I’m wondering about the same thing (letting FC get too low - it dipped to 1.5 last week).
 

capricatunes

Bronze Supporter
Jun 3, 2020
26
Minneapolis
pH of 7.2 is fine. Will not be there very long with TA of 110.

See if the water clears with normal target range FC. If not by tomorrow evening, then do Overnight Chlorine Loss Test
I ran the OCLT, and I lost no chlorine. CC have reduced. Still measuring at .5, but the pink color when adding R003 is more faint now.

The water is still cloudy. Any hypothesis? Thanks for your advice.
 

capricatunes

Bronze Supporter
Jun 3, 2020
26
Minneapolis
I would suggest raising your FC to SLAM level. Monitor for a day or two and see if it clears.
That did it. Better after 12 hours, and after two days we are back to crystal clear. CC = .5. Once the water clears up after a slam should I continue slamming for another 24 hours? Or can I let the root chlorine levels drop to normal now?
Thank you!
 

capricatunes

Bronze Supporter
Jun 3, 2020
26
Minneapolis
We got more rain yesterday, and once again the water has become hazy. I was surprised though, because the rain was minimal.
Before the rain, levels were fine (4.5fc, 30cya, 0cc, 7.6ph) and they held steady most of the day, just a bit of normal FC loss.
Is this just something I need to live with when it rains? Or are there any other hypothesis as to what could be doing this?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
32,524
Laughlin, NV
Do you get run off into the pool when it rains - including anything dripping from trees, etc?

Should clear. Your reported chemistry does not show any issue.
 

capricatunes

Bronze Supporter
Jun 3, 2020
26
Minneapolis
Do you get run off into the pool when it rains - including anything dripping from trees, etc?

Should clear. Your reported chemistry does not show any issue.
Thanks for the quick response. We do have a few branches that hang above the pool slightly, but nothing major. There may be some runoff from the surrounding cement patio, but again nothing major. I even scrubbed the shaded patio with bleach last week to ensure it didn’t have any algae build up.

The only other thing I can think of: 2 days ago the FC dropped to 1ppm. I wasn’t around so it may have been at that level for 12-24 hours. Could it be that a temporary lower level could result in hazy water two days later?

Otherwise, I guess our rain water here in Minneapolis just might not get along with my pool water...
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
32,524
Laughlin, NV
Depending on your conditions a FC below minimum is an invitation to algae. With that information, I suggest you take the FC to SLAM level today and see if it clears quickly.
 
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