Well balanced pool turned murky/cloudy/yellow when adding water to top off?

[akenis]

I swam Thursday evening, and pool was perfect. Friday is my maintain day. Check chem, run cleaner, add water and brush walls. So I put the hose into the shallow end, get my test kit and brush, and put the cleaner into the pool. A few minutes later I notice the shallow end is kind of murky and yellowish. Deep end is still clear and blue. The murky area seems to be spreading. Looking at the water stream coming out of the hose, I can see the stream is instantly changing color. 30 mins later and the whole pool is murky. A small bit of algae fall out on steps. Had to shock and keep cleaners going. All good by Saturday.

Florida West coast, Tampa area. What was this reaction with city water entering the pool?

 

[Texas Splash]

Two things we should start with:
1 - Do you fill the pool from a well?
2 - Can you post a full set of water test results?

 

[akenis]

Filled pool from same hose I always use. It comes from city water prior to my water softener.

See Pool Math export. Started fill around 10:30 probably. The TFT Pro test results are after pool was topped off (wanted accurate results with the new water added). CYA was a little low previous week, and I had added 3 lbs. pH was probably a little lower before adding water (I think it’s about 7.8 usually).

==========================================
Church Pool
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Build Type: Plaster
Volume: 18000 gallons
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Latest Test Result Summary:
FC: 3.0 (4 days ago)
pH: 7.8 (4 days ago)
TA: 73 (4 days ago)
CH: 475 (10 days ago)
CYA: 75 (4 days ago)
SALT: 3000 (10 days ago)
BORATES: 45 (10 days ago)
TEMPERATURE: 87° (4 days ago)
CSI: 0.01 (4 days ago)
==========================================
------------------------------------------
Maintenance 06-09-2023 @ 04:33 PM
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Vacuumed, Cleaned Filter, Brushed

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Chemical Addition 06-09-2023 @ 04:33 PM
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+ 33 Ounces of CalHypo73

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Chemical Addition 06-09-2023 @ 04:15 PM
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+ 47 FluidOunces of Baume31

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Chemical Addition 06-09-2023 @ 11:26 AM
------------------------------------------
+ 46 FluidOunces of Bleach

------------------------------------------
Test Results 06-09-2023 @ 11:22 AM
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CYA: 75
CSI: 0.01

------------------------------------------
Test Results 06-09-2023 @ 11:16 AM
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Free Chlorine: 3.0
pH: 7.8
Total Alkalinity: 73
Temperature: 87°F
CSI: 0.08

------------------------------------------
Maintenance 06-09-2023 @ 11:16 AM
------------------------------------------
Vacuumed, Brushed

 

[Texas Splash]

Okay, so two things stick out in your descriptions:
1 - The water color changes from the hose might be iron reacting to your chlorinated pool water. Iron water can have a yellow tint to it. Have you noticed any faded white/plastic items around the house? Might be something to watch. If you start to see more color changes in the water or staining let us know.
2 - You mentioned seeing (suspected) algae which seems odd since you just filled the pool unless the FC was allowed to drop too low in the past 4 days. As we approach summer, it takes no time at all for algae to grow in warm water, and if that happens, it's time to start the SLAM Process. Your CYA is basically 80, so a SLAM FC level of 31 is a bit of work.

For now, I would increase the FC to about 6-7 ppm with liquid chlorine. The intent is to try and take any stress off of the water and assist the SWG if it is overwhelmed by organics already. In addition, an elevated FC level can cause iron to react in the water, so if you have any doubts about iron in your local water supply, this may confirm it. But watch your FC level for sure.

If you see any other questionable debris in the water or suspect a heavy FC loss in 24 hrs, you should do an Overnight Chlorine Loss Test.

 

[Jimrahbe]

akenis,

To be picky...

If you had a "Well Balanced Pool" your FC would never be 3 ppm.

With a CYA of 70 your target is 5 to 10.

The idea is not to try to keep your FC between your minimum and your target, but rather it is to keep your FC at or above your target.

Thanks,

Jim R.

 

[JamesW]

Likely to be iron.

Pictures?

 

[akenis]

akenis,

To be picky...

If you had a "Well Balanced Pool" your FC would never be 3 ppm.

With a CYA of 70 your target is 5 to 10.

The idea is not to try to keep your FC between your minimum and your target, but rather it is to keep your FC at or above your target.

Thanks,

Jim R.

Thanks.. that CL reading was after adding 2” of un-chlorinated water. And a few days prior to this my CYA was down to 60 and CL was at 5.

 

[W.J.Christy]

Since you are on city water, do you know if they recently flushed the hydrants in your area? When that happens in my neighborhood, the water turns brownish yellow from all the silt and sediment that has accumulated in them getting stirred up.

 

[akenis]

Likely to be iron.

Pictures?

No pics. But when I went to buy Cal Hypo I got them to confirm my chem. Their printout said no iron.

I filled a tall glass from kitchen sink and set on window sill….looked clear to me (but this water goes through softener). A neighbor stopped by the next day and said toilet bowel water color looked at little off. Does water softener remove much iron?

BTW… if you click on my profile do you see a link to my pool math?

 

[Texas Splash]

Does water softener remove much iron?

It can, and I suspect your outside hose water has iron in it. Pool store testring is unreliable, even for metals. If you see tarnished percaline, that's probably iron.

 

[akenis]

Since you are on city water, do you know if they recently flushed the hydrants in your area? When that happens in my neighborhood, the water turns brownish yellow from all the silt and sediment that has accumulated in them getting stirred up.

Didn’t notice any hydrant activity. But did see this in the news…

How Tampa’s temporary water disinfection will affect residents

The Tampa Water Department is making temporary changes to its water supply as routine maintenance to preserve drinking water quality.

www.wfla.com

The switch to chlorine hadn’t occurred when I topped off my pool. But it is the same day they said they stopped purchasing water from Tampa Bay Water, as recent rains have alleviated drought conditions.

 

[duraleigh]

It's iron. Nothing else changes that rapidly and gives a yellowish/brownish tint

Since you are on City water I would divert any future pool refills through a whole house softener and that issue will go away.

 

[akenis]

It's iron. Nothing else changes that rapidly and gives a yellowish/brownish tint

Since you are on City water I would divert any future pool refills through a whole house softener and that issue will go away.

Thanks…. I’ve been doing this every week during the dry season, run hose for about 1/2 hour, without problems. Must have something to do with Tampa City stopping water purchase from regional water supplier Tampa Bay Water. My supplier is Pinellas County who also sources water from the regional Tampa Bay Water. Current Water Sources - Pinellas County

So when the big city stopped buying the regional water, my local Pinellas water changed somehow: “Tampa Bay Water’s system is a complex, reliable and sustainable water supply system. It’s not just unique to Florida. Tampa Bay Water is unlike any other water supply system nationwide because it blends river water, desalinated seawater, reservoir water and groundwater.”

I’ll do a visibility test on the hose water and get pool store to test that for iron.

My softened water is 0 ppm Hardness pretty much (per T.F. Calcium test). I thought it wasn’t recommended to add soft water to plaster pools because of leaching issues?

All moot soon as the rains pick up. I’ll be draining water every week…..