Lowering cya with ammonia then shock

[brg88tx]

Still a newbie here reading as much as i can about cya since i will soon have a new pool with an inline tab feeder. I came across someone saying that an old pool guy trick to lower cya without draining and refilling was to add 1-4 gallons of ammonia then a day or 2 later shock it heavily.

Has anyone ever tried this and what were your results? thanks

 

[chem geek]

Very unlikely. Of course, anyone can try this sort of thing using small quantities of ammonia and chlorine shocking in a bucket of pool water and see what happens.

 

[Freelancer]

Sounds like an interesting project.. I have 5Kg of CYA dissolving in 50 litres of water and i have plenty of ammonia so I'll use some of that in a bucket and will report back my findings.

 

[JamesW]

I think that the technique you are referring to is using ammonia to treat algae when the cyanuric acid is high.

Ammonia forms chloramines, and can be effective at killing algae when the cyanuric acid is high. However, it is usually better to just lower the cyanuric acid by dilution.

I have never heard of using ammonia to lower the cyanuric acid level, and I don't think that it would do anything to the cyanuric acid level.

 

[JasonLion]

I've never heard of that one, nor does it sound likely to work. As JamesW said, that is very similar to an old trick for killing algae when CYA is high.

 

[brg88tx]

i actually read this on another thread on this forum, posted back in 2008. here it is:

KCAZ Post subject: Re: Degradation of Cyanuric Acid (CYA)Posted: October 27th, 2008, 4:22 pm
New User

Joined: October 27th, 2008, 4:00 pm
Posts: 9 Report this postReply with quote

Interesting thread. I have a pool biz in AZ and we often run into high CYA issues here due to extensive use of tri-chlor tabs and di-chlor shock by pool owners and many poolmen. Lots of sun and warm water compound the problem. I personally like to keep my CYA under 70ppm and find that this works well here.

I recently acquired some pools which were heavily overstabilized (CYA 150+). I am running into resistance from cash-strapped pool owners that do not want to spend the money to drain and re-fill. They think the new pool guy is just trying to take their money because the old guy would just throw tabs in and shock the **** out of the pool when the algae bloomed. We all know that this cycle of tab and shock cannot continue forever with CYA over 150.

This leads to my question about alternate ways to reduce the CYA. I have been told that heavy doses of ammonia (1-4 gallons) followed 24-36 hours later by heavy shock will knock out the CYA. I have searched the net far and wide and have not been able to confirm this old poolman trick.

Does anyone have any info as to the validity of this method?

Thanks in advance for the replies.

 

[brg88tx]

Sounds like an interesting project.. I have 5Kg of CYA dissolving in 50 litres of water and i have plenty of ammonia so I'll use some of that in a bucket and will report back my findings.

i'm interested to see your findings Freelancer.

 

[Freelancer]

I made up a batch of water with 199 PPM of CYA.. In the test cup I put just a quarter tea spoon of ammonia the reading went from 199 to 207.

I suspect not all the CYA in my batch was in suspension and that the ammonia actually aided the CYA into suspension.

I used the Palintest pooltest 9 premium which gives extremely accurate readings.. One note is that when you put the melamine tablet into the test tube and mix it initially you will think all the CYA has gone, the tablet will completely dissolve and the water will be clear, give it a few minutes and the milky cloud will appear.

Given the amount of ammonia I put into a cup if there was any truth in this method then I'd have seen some drop but I did not and can therefore say that ammonia does not get rid of CYA oh and if you are going to do this then may I suggest you do it outside, I half chocked myself on the ammonia, strong stuff.. Nose is nice and clear now though so not a complete waste of time.

 

[chem geek]

You need to wait and then shock the water with chlorine -- I don't think they were saying that ammonia alone was enough. It's the ammonia plus chlorine that they claim does the trick. Did you try that or are you just waiting the 24-36 hours and will then shock with chlorine and let us know if anything happens? Or do you think the wait was to have the "process" work and the later shock with chlorine was to get rid of the resulting ammonia? Anyway, I doubt this will work in any event.

 

[Freelancer]

Richard I'll wait 24 hours and then will shock the water with chlorine but to be honest like you I doubt if the CYA will change at all but we'll see.. Might as well go through the whole process to prove or disprove the theory.

 

[brg88tx]

Richard I'll wait 24 hours and then will shock the water with chlorine but to be honest like you I doubt if the CYA will change at all but we'll see.. Might as well go through the whole process to prove or disprove the theory.

any update freelancer?

 

[ivyleager]

Hoping freelancer is okay. The mixing of the chlorine and ammonia had me worried.

 

[Freelancer]

Sorry guys was a bit busy yesterday but will be shocking the sample this afternoon and then allow 36 hours for the process to work will then take some readings and will post my findings.

 

[Shane1]

This is like Mythbuster ! I'm glad I found this thread. PleeeeaaaSe keep us in the loop

.

 

[Freelancer]

OK here are my latest findings.

The water sample (10 Litres) with 207 PPM CYA had 20ml of Ammonia put in. Water was retested. CYA remained the same at 207 PPM.

Water was left to stand for 48 hours. I then put 20ml of 4% bleach into the 10 Litre test water.

I let it stand half an hour. Retested the CYA, readings were exactly 207 PPM.

Let it stand for a few hours and retested.. 207 PPM

The calculated FC level is around the 80 PPM mark, this I did using the pool calculator suffice to say it bleached my DP1 tablet so I know there was a lot of chlorine in the water.

I'll leave the water to stand for day and retest but to be honest if there was going to be any reduction then I would have expected the process to at least have started and seen some drop in the readings but there was not one PPM drop after a few hours.

Myth busted...

 

[chem geek]

Myth busted...

Thanks for doing this. Though I have a pretty strong faith in what the theoretical chemistry says about such things, one never knows that something obscure or hitherto unexplained is going on so an experiment is really the only way to fully debunk such myths.

 

[Freelancer]

On a final note, having left the solution for two days now I have retested the sample solution CYA and it remains at 207 PPM. I think that it is safe to say that there is no truth in this method. So other than clearing your sinuses or relief from those irritating bug bites there is no cause to put ammonia in your pool water.

 

[frustratedpoolmom]

fantastic thread...thanks guys!

 

[jldelia]

The chloramine vapors produced by mixing ammonia and chlorine are extremely toxic. I don't suggest anyone else performing a similar experiment.

 

[chem geek]

Welcome to TFP!

The experiment was already done and the myth busted. We were talking about small quantities of chlorine and ammonia in a larger volume of water, not concentrated solutions.

I agree you do not want to mix those concentrated chemicals together, but that wasn't the experiment. The original quantities of 1-4 gallons of ammonia and then shocking with chlorine are very dilute in a pool with many thousands of gallons of water. The bucket experiment would use similar scaling of dilution or perhaps somewhat more concentrated, but certainly not only ammonia and chlorine themselves. 20 ml of ammonia (household ammonia is usually 5%-10%) was put in 10 liters (10,000 ml) of water and 20 ml of 4% bleach was also used. The amount of FC added was around 80 ppm and if that produced monochloramine that is not enough to produce noxious monochloramine vapors though the smell could be noticeable. It would be VERY irritating to the eyes underwater so is not something to swim in, but that wasn't the experiment.

Note that the Coral Seas® Green to Clean® product has this MSDS showing it is essentially EDTA with ammonium sulfate. When added to a pool with chlorine, it will produce monochloramine which kills green algae even in pools with high CYA that would prevent chlorine from doing so. As shown in their instructions, one should never pre-mix their concentrated chemical with chlorine. Their instructions raise the FC level to 10 ppm and since 28/(292-2+46+36+132) = 5.5% of the weight of their product is ppm N from ammonia that would be 0.9 ppm N (from 16 mg/L of added product). This would initially and quickly form around 4.5 ppm CC as monochloramine though over hours would get partially oxidized by excess chlorine. They then later superchlorinate to further oxidize the monochloramine to get rid of it.

Anyway, there's no reason for anyone to now do the experiment since it was already done and demonstrated that the CYA was not reduced by this method. It didn't make much sense that it would, but it was worth a test.