Did ammonia eat my cya over the winter then evaporate?

pookiesunshine

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May 12, 2016
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Cincinnati, OH
Pool Size
33000
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Chlorine
Liquid Chlorine
i've looked over some old threads about ammonia and that has me pondering this question.

First some background:
i have a mesh cover that lets in sunlight, dirt, etc. Normally upon opening i find a lot of silt and earthworms. this is my first opening after converting to chlorine. i found NO earthworms this year.
When i closed, i dosed chlorine to shock level the day before and added some algaecide. Now i know the algaecide was probably not a good idea and dont plan on that this time.
CYA at closing was around 40-50. At opening cya was zero.
Opening was to a green swamp but it cleared up in a week using bleach, not technically a slam.
I did NOT notice any particular spike in CC nor have great difficulty in getting FC levels up. yes, i consumed a bunch of bleach, but no CC spikes nor the experiences i would have expected from reading the prior threads on ammonia problems.
Something formed a coating on the bottom that i could not see directly because the water was so dirty but seemed to flake off during the clean up process. I thought it was leaves, but later discovered it was something else, sometimes attached to leaves, other times it was just slimy flakes in various shapes-one looked like a dead squirrel, one a bat, etc. weird.

Where did the cya go over the winter? why no earthworms for the first time in over 20 years?

My hypothesis: Over the winter, FC went to zero, earthworms contributed a source of bacteria to convert cya to ammonia (consuming the earthworms in the process or converting them to an unrecognizable form), then the ammonia dissipated through the mesh cover before i opened the pool.

Does this make any sense or do you have another idea of what happened?
Should i just forget it and go worry about something that makes a difference? Wait, i hear a beer calling....
 
LOL! Well, listen to the beer first! :cheers:

Given enough time bacteria can convert CYA to ammonia and then more bacteria can convert ammonia to nitrites and then given even more time bacteria can convert nitrites to nitrates. It is called the nitrification process.
 
How much precipitation do you get in the offseason?

Here in PA we get a ton, and I open to a swampy pool with 0 CYA each year. I'm 99% sure it's dilution from all the rain/snow since my salt and calcium levels are always way lower as well.
 
How much precipitation do you get in the offseason?

Here in PA we get a ton, and I open to a swampy pool with 0 CYA each year. I'm 99% sure it's dilution from all the rain/snow since my salt and calcium levels are always way lower as well.

Interesting. I'm not that far from you, but think about it. If dilution is the only reason for the cya drop, wouldn't you also expect salt and calcium to show massive losses? How much lower were those? My salt level was about the same, maybe 10% lower, but i think that is easily within test error or dilution. cya on the other hand showed 100 percent loss. so while dilution may play a part, i dont see it being a major factor, at least in my case. I dont lower my water level at closing any more; though i used to 10 years ago. So precipitation accounts for less than 10% dilution over the winter for me. If you drop your water level considerably at closing, i can see how you could get 30% dilution easily, but not me.
 
You two are both saying the same thing. And your theories are correct. With dilution all levels, CH, salt and CYA, will drop relative to the amount of dilution.
 
Interesting. I'm not that far from you, but think about it. If dilution is the only reason for the cya drop, wouldn't you also expect salt and calcium to show massive losses? How much lower were those? My salt level was about the same, maybe 10% lower, but i think that is easily within test error or dilution. cya on the other hand showed 100 percent loss. so while dilution may play a part, i dont see it being a major factor, at least in my case. I dont lower my water level at closing any more; though i used to 10 years ago. So precipitation accounts for less than 10% dilution over the winter for me. If you drop your water level considerably at closing, i can see how you could get 30% dilution easily, but not me.
The CYA test is too approximate to say for sure. If you closed with 40 CYA, you could easily re-open to 20-30 from all the dilution. And at low CYA ranges like that, it's very easy to mistake a little CYA for 0 CYA.

Unless you A) Cannot hold a CYA after opening B) lose more than 50% FC within minutes of starting your SLAM or C) Do an Ammonia test that returns positive results, I would suspect dilution over ammonia.
 
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