What the heck got in my pool?

yitbos1

Member
Jun 20, 2008
22
Wichita, KS
Just got back from a 5-day vacation where a friend was house sitting and performing all of the daily pool maintenance duties (add bleach to the Liquidator, watch water level of pool, empty strainer, etc.). Received a call from him during the 4th day saying that the pool was really cloudy. The day or two prior, it rained quite a bit, so I thought that might have had something to do with it, so I didn't really think much of it. Today - the first day back - I see that the pool is cloudy to the point where the bottom of the shallow end (3') is not visible. I note that not nearly as much bleach was added to the Liquidator as should have been so I just thought is was an algae outbreak. A test of the chlorine levels shows only about 1 ppm FC and 1-2 ppm CC (My CYA level is about 50) - much to be expected. I also checked my pH as an afterthought and it was really low. It was reading 6.8, so I added Borax. It took a whole box to get it up to about 7.2.

So I start shocking...

Typically, it only takes a bottle or two of bleach to go from green to cloudy and holding FC, but now that I'm 6-7 bottles into it, I'm starting to wonder if something else is going on. Here's a rundown of the stuff I'm observing:

1. The cloudiness wasn't green as you would expect from an algae outbreak.
2. I've been checking the FC every hour or two after bringing it up to shock level and in the beginning, the chlorine was consumed almost immediately. Now at the end of the day, FC is about half after an hour or two.
3. Every time I've checked, CC has been constant at 1.5 - 2 ppm.
4. The cloudiness has dissipated throughout the day from not being able to see the bottom of the shallow end to being able to see the bottom of the deep end (about 6 1/2').
5. The surface of the water is foamy. I'm not talking too-much-detergent-in-the-washing-machine foamy - just a fine layer of foam collecting on the surface.

The more I think of it, the more I think what is going on with the pool is not caused by algae. The water was never green to begin with and my filter pressure has not budged while the pool has been clearing. This leads me to believe the filter isn't really filtering out what is causing the cloudiness. As I go to bed, I will probably have to add a few more bottles of bleach based on what I've seen so far. There is still some cloudiness and FC isn't holding.

What the heck is in my pool??? Anybody have any idea what I'm fighting?
 

NWMNMom

TFP Expert
LifeTime Supporter
Apr 8, 2007
1,582
Waaay NW MN
You are positive they didn't add some other chemical to the pool in your absence? Did the rain knock a lot of tree pollen or other substance into the pool? Was there any kind of big wind that would have blown something in there?
 

JasonLion

TFP Expert
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May 7, 2007
37,880
Silver Spring, MD
That sounds like fertilizer and insecticide or weed killer, or something along those lines. Chlorine will take care of it, but depending on how much got into the pool it might be a while.
 

yitbos1

Member
Jun 20, 2008
22
Wichita, KS
NWMNMom said:
You are positive they didn't add some other chemical to the pool in your absence? Did the rain knock a lot of tree pollen or other substance into the pool? Was there any kind of big wind that would have blown something in there?
I also thought something was added to the pool that shouldn't have been, but if there was, it wasn't the person that was watching the house. If something was put in the pool, it was either an effect of weather (not likely - this is MUCH worse than anything I've seen before) or an act of maliciousness. I may never know.

At any rate, FC was back to about 1 ppm this morning with CC still at 1.5 ppm. The water is almost completely clear now, which makes me think I'm nearing the end of whatever it was causing the cloudiness. pH was back to 6.8-7.0 again, so I added more borax before bringing the FC back up to shock level. Foamyness is still there.
 

yitbos1

Member
Jun 20, 2008
22
Wichita, KS
Update: I thought I'd check my CYA since I was checking other stuff. IT'S GONE! I had a CYA of about 50 a month ago, now it ZERO or very close to it! I first thought my CYA reagent was bad, so I retrieved the new bottle I just bought from duraleigh's outfit. Same result! What the **** is happening!?!?!?
 

JasonLion

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May 7, 2007
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Silver Spring, MD
Sometimes when the FC level goes to zero, there is a kind of soil bacteria that can start growing in the water which eats CYA and produces ammonia. This is quite rare in an uncovered pool, since that bacteria prefers water without oxygen, but does occasionally happen even without a cover.
 

yitbos1

Member
Jun 20, 2008
22
Wichita, KS
JasonLion said:
Sometimes when the FC level goes to zero, there is a kind of soil bacteria that can start growing in the water which eats CYA and produces ammonia. This is quite rare in an uncovered pool, since that bacteria prefers water without oxygen, but does occasionally happen even without a cover.
Gotcha. Makes sense. The pool was covered for most of the time we were gone, so that fact seems to fit what you think happened. Now that I think about it more, could that have been what got in my pool in the first place? All the rain we had could have deposited it in my pool and it grew there in the couple of days afterward that there was no chlorine in the pool. Couple that with the high temps we've been seeing and, voila, prime breeding ground for bacteria. All the ammonia it produced is what is taking all the chlorine to get rid of. I wish I would have known about this earlier since I have some ammonia test strips. The infestation is gone now as my FC pretty much held overnight. There is still about 1 ppm CC, though, which has me confused. If the FC held overnight, I would have thought there wouldn't be any CC. There was still a bunch of foam on the surface of the water which might have been the source of the CC. I skimmed that off in much the same way that oil spills are cleaned up so we'll see if that fixes it.

So are the following observations consistent with a soil bacteria infestation/ammonia?
* Cloudy water
* High chlorine demand/CCs
* Persistent foam
* Covered pool
* Occurred after significant rain
* Plummeting pH
* Consumed CYA
 

JasonLion

TFP Expert
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LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
Yes, that all fits.

CC is really a collection of a whole variety of different compounds, some of which break down quickly and some of which break down slowly. After fighting ammonia it is common to have some of the slow to break down kind left over that takes a couple of days to go away, even though FC levels remain relatively stable. Sunlight helps get rid of hard to break down CC.
 

yitbos1

Member
Jun 20, 2008
22
Wichita, KS
That's it then. Thanks for the diagnosis! I was starting to think somebody was pulling a prank on me, but the CYA loss really confused me. I really appreciate your help in the matter, JasonLion! I will make sure to have a beer by my clear-and-still-somewhat-foamy pool for you! :cheers: