CYA from 60 to 0 ppm

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E

Exchemist

0
Oct 5, 2007
86
Philadelphia, PA
When I opened my pool this spring, the CYA was 60 ppm. I checked the level again a few weeks ago and, as expected, it was still 60 ppm.

I went away on travel and vacation from July 14 to 21. When I was away, I set up a Hayward chlorinator with four pucks and had a neighbor monitor the water level. I kept a solar cover on to minimize water and chlorine loss. It was very hot while I was away. The neighbor needed to add water at least two times. The chlorine demand was much higher than I expected and the chlorinator could not keep up.

When I returned, the pool was very cloudy, not green but gray and the chlorine was near zero. I used liquid chlorine to bring the chlorine to shock level for 60 ppm CYA and the pool cleared in about three days. I've been using liquid chlorine now that I'm in town and noticed that the chlorine demand is much higher than before I went away. I also noticed that the demand was twice as great on sunny days.

So, I just remeasured the CYA level. It was zero. Measured again using a new reagent bottle. Still zero. Brought a sample to the local pool store and they measured zero as well. I'm convinced it really is zero.

I'm now adding two pounds to CYA, which should bring the CYA level to around 20 ppm. If this occurs, I'll add another two pounds which should bring me to 40 ppm.

I believe that there was a bloom of anaerobic bacteria while I was away. This is why the pool was cloudy when I returned. The low chlorine level and solar cover probably is what allowed the bacteria to grow. The bacteria consumed the CYA leaving me with zero.

I'm now a believer in CYA-consuming bacteria. Through I never would have thought the level could go from 60 to 0 ppm in nine days. Consider this another data point in the debate.
 
JasonLion said:
If only there was a way to get this to happen on demand. A week of cloudy water and shocking would be better than a near total water replacement for many people with extremely high CYA levels.
Click to expand...
Maybe we should figure out what form of bacteria it is, and sell it.

Directions:
  • 1.) Add special CYA reducing bacteria to pool.
    2.) Do nothing for 1 week.
    3.) Follow TFP "How to clean up a green swamp" instructions.

Maybe Dave can add this to his product lineup. :-D
 
waterbear said:
The kinds of bacteria are well known. Some are of the type psuedomonas.
Click to expand...
Here is a quote from a patent filing in 1996:

"The present invention provides for substantially complete degradation of
s-triazine compounds, preferably chlorinated s-triazine compounds, and
more preferably atrazine. The initial concentrations of the s-triazine
compound can range from trace amounts to thousands of pans per million
(ppm). These values represent the initial concentration of the s-triazine
in an aqueous solution containing the s-triazine compound, the bacterium,
and the aqueous media. It is to be understood that a "trace" amount refers
to the lower limit of detection of the assay techniques described in the
examples below, which typically is approximately 2-3 parts per billion. As
used herein "rapidly" and "substantially completely" means that about 90%
of the initial concentration of the s-triazine compound in an aqueous
solution is degraded in about 180 minutes."

I know very little about chemistry, but I'm wondering if this would be relevant. I wonder if the patent ever led to any commercial product being developed.....
 
The scenario Exchemist reports sounds exactly what happened to me.(See http://www.troublefreepool.com/back-from-vacation-w-cloudy-pool-no-cya-t8420.html). What may be of particular interest is the description of the water.

"When I returned, the pool was very cloudy, not green but gray and the chlorine was near zero"

Again, this prefectly describes the water in my pool upon returning from vacation. I wonder, for future reference, could this grayish cloudiness could be an indication of anaerobic CYA-consuming bacteria?
 
The grayish cloudiness is more likely to be algae. Some pools with the drop in CYA with no chlorine levels have been clear.

Since a byproduct of the breakdown of CYA is ammonia, the presence of ammonia is a pretty clear indicator that biodegradation of CYA has occurred. However, ammonia can dissipate from the water over time, but if present it will seem like an unusually high chlorine demand. Ammonia can generally be measured by an inexpensive test kit found in pet/fish/aquarium stores.
 
Based on the comments, I've given this some more thought. Getting the conditions for the right bacteria is improbable which is why this is so uncommon. Based on what happened, I'm guessing the right conditions include:
1) Dosing the pool with soil dust. (It was very dry here for two weeks before I left and the pool collects significant amounts of soil dust and sand blown. I also did much work on the landscaping this spring. I added 16 cu yds of mushroom compost and spread 14 cu yds of hardwood mulch around the house. I'm sure my pool has a constant supply of soil bacteria.)
2) Low oxygen. (Pool mostly covered. Due to a mistake when I ordered the cover, the cover only covers about 90% of the pool.)
3) Near zero chlorine.
4) Circulation.
5) Minimal or no light. (My pool cover is a dark blue and lets very little light in.)
6) pH of 7.0 - 7.2. (This was the ph of my pool when I returned.)

Anyone with high CYA feel like doing an experiment?
 

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Cyanuric acid normally degrades very slowly under aerobic conditions. However, it can be degraded if specific fungi or bacteria strains are present, the microorganisms have been acclimated to cyanuric acid, and organic nutrients are present.

Only one (the fungus Sporothrix schenckii) of 160 microorganisms tested by Zeyer gave significant degradation of cyanuric acid under aerobic conditions. They found rapid degradation to carbon dioxide and ammonia and that all of the liberated ammonia was incorporated into biomass. The soil fungi Stachybotrys chartarum, Hendersonula toruloidea, Penicillium sp. and Hormodendrum masonii have also been reported to degrade cyanuric acid.
Several types of bacteria, including an unidentified mixed culture, Pseudomonas sp., and Achromobacter sp. can degrade cyanuric acid. The bacteria grew under aerobic conditions with cyanuric acid as the only source of nitrogen. Cyanuric acid is readily degraded in the aerobic, activated sludge process used by the municipal wastewater treatment plant receiving waste from a chlorinated isocyanurate manufacturing plant in Illinois, USA. The extent of degradation averages about 85%. Weber and coworkers report that cyanuric acid is readily degraded in aerated, activated sludge under nitrogen-limiting conditions.Cyanuric acid is not an energy source for the bacteria, since the degradation is a hydrolysis. Cyanuric acid is converted into carbon dioxide and ammonia. The ammonia is then incorporated into the biomass or nitrified.

Anaerobic biotransformation -Saldick found that cyanuric acid biodegrades readily under a wide variety of natural conditions, and particularly well in systems of either low or zero dissolved oxygen level, such as anaerobic activated sludge and sewage, soils, mud, and muddy streams and river water, as well as ordinary aerated activated sludge systems with typically low (1 to 3 ppm) dissolved oxygen levels.


Cyanuric acid is biodegraded under anaerobic conditions by some strains of bacteria, such as Pseudomonas, Klebsiella pneumoniae, and others, into carbon dioxide and ammonia. Eaton and Karns located the gene that encodes the cyanuric acid aminohydrolase enzyme responsible for hydrolysis of cyanuric acid in three strains of bacteria.

Cyanuric acid is also taken up and degraded by plants. Cyanuric acid acts as a slow release nitrogen fertilizer, although it showed some toxicity to plants at higher levels, similar to some other nitrogen fertilizers.

Degradation also proceeds in 3.5% sodium chloride solution.
 
PoolOwnerNumber9,

Thanks for the additional detailed info. The biodegradation pathway may be seen here though they don't properly count the amount of ammonia in the last step (i.e. it's not balanced equations, but rather just showing products).

Dave (duraleigh),

Not to worry. The degradation requires living bacteria and the use of chlorine prevents such bacteria from surviving in sufficient numbers to produce such degradation. It would be nice if one could "turn on" this process at will to lower CYA levels when desired, but for now this seems to be fairly uncontrolled. I'm certainly not using my own pool in such an experiment. :shock: Of course, one could use buckets of simulated pool water, if so inclined.

Richard
 
I think that an important point was lost in the above discussion. That is when CYA is being consumed, the pool is white or gray. I had the same experience. I believe that the organic agent responsible for the consummation of CYA produces a gray or white haze to the water when present is large quantities.
 
Got it. We'll have to keep track to see how prevalent this cloudiness is. As I noted earlier, some pools that had CYA disappear over a winter of being "let go" were clear, not cloudy, so it's not consistent. It's possible that sufficient amounts of bacteria clump to make the water cloudy, but I think it more likely that the cloudiness is due to algae starting to form since there is no chlorine in the water. Algae can be present first as clear water, then dull, then cloudy before it accumulates enough to look green (this depends on the type of algae; some have the water look green earlier and not as cloudy).

Since the byproduct of the degradation is ammonia, I think an ammonia test would be pretty definitive since ammonia should not be in the pool in large quantities except from such CYA degradation. The problem is that ammonia can be taken up by algae so perhaps the end result of CYA degradation is clear water with lots of ammonia or cloudy water (from algae) with little or no ammonia. That would be consistent with the results that have been seen.

Richard
 
dschlic1 said:
I think that an important point was lost in the above discussion. That is when CYA is being consumed, the pool is white or gray. I had the same experience. I believe that the organic agent responsible for the consummation of CYA produces a gray or white haze to the water when present is large quantities.
Click to expand...

Exactly...when this happened to me, the cloudiness was so bad that one could only see about 18 inches down. Color was milky white to grayish and did not look like algae (not a tinge of green anywhere). I understand that when an algae bloom is killed off it can turn this color. Remember, in these instances the pool's chlorine levels depleted over a weeks time. Should algae form, there would not be enough Cl2 to kill it and turn it white.
 
Perhaps some chemical, similar to melamine, is combining with the cyanuric acid causing it to precipitate out of solution. Pools that are circulating would be cloudy and milky, pools that were off for a while may be clear due to the precipitate falling to the bottom.

Is there any such chemical that could be getting in a pool? Is there anything that the water supplier adds to the water that would combine with the Cyanuric acid? Could anyone who has experienced this contact their water supplier and ask them about this?

This topic (Controlling or degrading Cyanuric type compounds) seems to be of interest to several government and industrial organizations. Does anyone think that it would be a good idea to contact someone involved in this kind of research? If they were interested, we could post their address, and ask anyone experiencing Sudden Cyanuric Acid Loss Syndrome (SCALS) to mail a sample of their water to the researchers for analysis. I think that this could be beneficial to us and them.

I would also ask that anyone experiencing this immediately test for ammonia before they shock or do anything else so that we could try to determine if this is a biodegradation or a precipitation.

I also think that the “mushroom compost” that exchemist mentioned may be relevant. Mushrooms are a fungus or fungi. As noted above some fungi can biodegrade Cyanuric Acid.
 
There's nothing like melamine in the pool that should precipitate any remaining CYA. Perhaps it is just lots and lots of bacteria -- they would make the water dull to milky gray and not be algae, but it would take a heck of a lot of bacteria to do so. This sort of problem could also happen in an aquarium (i.e. lots of bacterial growth if things aren't kept in proper balance) so perhaps waterbear has some experience with this and could chime in on what it looks like. I'm probably just wrong in thinking it's not bacteria [EDIT] for the milky cloudiness [END-EDIT] -- it probably just is [EDIT] and we know that bacteria is what degrades CYA to ammonia [END-EDIT].

Richard
 
I already have chimed in and people have gotten upset with me when I said algae does not consume CYA but bacteria does.so I will sit this dance out for now.
 
Here are some quotes and reference sources:
_______________________________________________________________________________________________
http://www.epa.gov/HPV/pubs/summaries/s ... 4660rs.pdf
http://www.pubmedcentral.nih.gov/picren ... obtype=pdf
http://www.pubmedcentral.nih.gov/articl ... tid=186872

Cyanuric acid is also taken up and degraded by plants. Cyanuric acid acts as a slow release nitrogen fertilizer, although it showed some toxicity to plants at higher levels, similar to some other nitrogen fertilizers.

Biodegradation of cyanuric acid also takes place in systems of considerable salinity.
Here is the chemical equation for the breakdown of Cyanuric Acid.
C3H3N3O3 + 3H20 = 3CO2 + 3NH3.
Cyanuric Acid + 3Water = 3 Carbon Dioxide + 3 Ammonia

Degradation also proceeds in 3.5% sodium chloride solution.
_______________________________________________________________________________________________

According to one source, cyanuric acid is degraded by plants. I would assume that includes algae. I would also assume that the carbon dioxide combines with the water to produce carbonic acid.
CO2 + H2O = H2CO3
 

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