ammonia problem

[Very Frustrated]

We were told by our pool maintainance company that we have a chlorine lock and the pool tested high ammonia (3 times normal). Long story short: This is the 4th time between last year and this summer that we've had to drain the pool down and refill and I'm sick of it. We don't know what the source of the ammonia is - don't fertilize, no huge crowds of people, pool vinyl lined, auto chlorinator, 12 years old and never had a problem until last summer.
Oh, by the way, the drain/refill last week only took the ammonia level down to 2 so we may have to do it again. Very expensive and in the meantime, nobody is swimming! Anyone have any experience in this?

[me_too]

We were told by our pool maintainance company that we have a chlorine lock and the pool tested high ammonia (3 times normal). Long story short: This is the 4th time between last year and this summer that we've had to drain the pool down and refill and I'm sick of it. We don't know what the source of the ammonia is - don't fertilize, no huge crowds of people, pool vinyl lined, auto chlorinator, 12 years old and never had a problem until last summer.
Oh, by the way, the drain/refill last week only took the ammonia level down to 2 so we may have to do it again. Very expensive and in the meantime, nobody is swimming! Anyone have any experience in this?

Ammonia? Do they mean phosphates?

You may be just high in CYA since you're using a chlorinator. What's your CYA number?

Post a complete set of test results (and pool size) and we'll take it from there.

[Backglass]

Chlorine lock is caused by high levels of CYA (stabilizer). After you get the levels down, switch to liquid chlorine. If you go right back to pucks and dry shock, you will eventually be back in the same (locked) boat again.

The ammonia is coming from <DRUMROLL> Your kids! Perspiration and Urine are mostly ammonia but because of the chlorine lock, they couldn't be removed and thus built up.

Chlorine (when free & available) oxidizes Ammonia and Nitrogen. Fix the chlorine and you fix the ammonia.

...and don't double post! Once is enough.

[bluecubsfan]

I read your post and thought that perhaps I had written it! The same thing has happened to me the past 2 years upon opening the pool. Last year I was told that I had waited too long to open it.
This year that can't be the reason. I am taking the water level down below the the returns tonight and refilling tomorrow. I will try the liquid treatment that was suggested and see if that helps. Good luck solving your problem.

[chem geek]

It is well known that bacteria can convert Cyanuric Acid (CYA) into ammonia resulting in a very large chlorine demand. However, the bacteria won't grow unless the chlorine level goes to near zero. So this problem usually only happens when one closes a pool over the winter and stops adding chlorine (which you can't help if your pool freezes over and you drain below the returns).

Though normally the conversion of CYA to ammonia occurs over an extended period of time, it can literally take just a few days as happened to my own pool as I describe here.

At the end of this season I will do an experiment and let the chlorine go to zero and see how long it takes for algae to grow or for the CYA to start dropping. I added 50 ppm Borates to the pool so am curious to see if this inhibits algae growth and by how much. My pool has 2000-3000 ppb phosphates so is very unforgiving if the chlorine gets too low, but I normally have no problems with the pool since (except for this one time) I keep the FC/CYA ratio high enough.

Richard

[Bonnie]

I may have to disagree about the cnyaric acid being the answer to the problem. I have several customers with low cynaric readings and they are still experiencing ammonia problems. I have recently tested the rain water and found that there were high amounts of ammonia present. We do a partial drain sometimes and still treat with extreme amounts of sodium dichlor. The average amount of dichlor at one time is 10lbs or more depending upon the size of pool we also re-check our ammonia reading in 48 hrs to see how much we have burned out. There are some occasions the pools become so green we use a dry floc which if you allow it to send everything to the bottom of the pool it ususally works very well. It just requires patience because sometimes it takes 5 or 6 days to work. We have found that any pool that we have on borates do not experience this problem or regualar doses of copper algaecide sometimes offer a good defense. I prefer the borate that is what i use and i have had no problem with the ammonia compared to my neighbors who have had the issue. I have been in the pool business for 25 years and have never had the problems we have experienced the last 3 years. For all of you who are frustrated you are not the only one and don't give up and be willing to change your methods. Please have your pool checked before you close it we have found the problem can become really nasty if you don't remove them before you close it. Also make sure you are dealing with a reputable pool dealer, retail and hardware stores are not trained or have any knowledge about this particular problem.

[lbridges]

Very Frustrated - if you read the link that chem geek provided you will find that adding sufficient (large) quantities of bleach (or pool store chlorinating liquid if cost effective) will eventually oxidize all the ammonia away.

[chem geek]

I may have to disagree about the cnyaric acid being the answer to the problem.

I never said that Cyanuric Acid was the answer to the problem. Indeed, I said that when the chlorine level gets to near zero, bacteria can grow and convert cyanuric acid to ammonia. This is described technically in this post including links to scientific sources describing the chemical pathway involved.

As noted in this link, the ammonium ion concentration in rain water is at most 0.65 mg/L (ppm) which isn't very much considering the amount of rain relative to pool water volume. It isn't going to be a particularly significant factor. Even with a 4" rain in a 4' deep pool, this nets out to only around 0.05 ppm ammonia introduced into the pool requiring around 0.5 ppm FC to get rid of it.

The large quantities of ammonia can come from the bacterial conversion of CYA into ammonia since for every 10 ppm CYA converted it produces around 3 ppm ammonia and that can require 23-30 ppm FC to get rid of it. So having CYA levels drop when the FC is near zero can certainly be a sign of such conversion, especially if ammonia in significant quantities is measured in the pool water.

[Guest]

ok- I work at a pool chemicals and service business in Indiana and cyanuric acid levels have nothing to do with ammonia problems. Ammonia is an air born substance, probably from treating grass or farmers use it to grow crops. Even if you do not live near neither of these things, like i said it is still an air born substance so it can travel. Even a couple miles and get into your pool. The way to get control over this substance is to double shock your pool. Grainular chlorine is idea, super shock wave is a good example, becuase it contails a 73% active compared to other chlorines like liquid that only has 12% maximum you can get. We tell customers to add 1 pound per 1000 gallons. So lets say you have a pool containing 2000 gallons, we would want to put four pounds to double shock it. Do that 3 nights in a row if the ammonia problem is high. Then go to the nearest pool business and get your water tested, specifially for ammonia. You have to continue to shock this problem until it is powerful enough to overcome. Then once it is gone, make sure to keep the chlorine high at all times, so this does not become a problem again, becuase it is not cheap to fix. Good luck

[chem geek]

This is not true. Chlorine reacts almost instantly with ammonia to form monochloramine which measures as Combined Chlorine (CC) in test kits, but then gets further oxidized (within hours) to nitrogen gas (and some nitrate). The most common ammmonia test kit based on salicylate does not distinguish between ammonia and monochloramine (the less common kit based on Nessler's reagent has less interference from monochloramine). Ammonia, presumably in the form of ammonium nitrate from fertilizer, is not blown into pools in any quantity large enough to be measurable (i.e. at the ppm level) and it is oxidized relatively quickly by chlorine so would not result in a huge amount of ammonia. Ammonia can most certainly result from bacterial conversion of CYA. That's known science (did you read the links I gave? can you read and understand this link and the detail in this link and this link that show ammonia being produced by the bacterial degradation of cyanuric acid? Or how about this link, this link, and this link among many others).

I believe what you are thinking about is phosphates (and nitrates) from fertilizer which can get blown into pools since much smaller concentrations (in the hundreds of ppb range) can create greater chlorine demand. These are essential nutrients for algae growth so if one does not have sufficient Free Chlorine (FC) relative to the Cyanuric Acid (CYA) level, then algae can grow faster than chlorine can kill it. In that situation, it can appear as if one has an unusual chlorine demand since the algae can be growing and using up chlorine without yet being visible. Shocking the pool to a higher chlorine level to get ahead of the algae growth would work in that case, but if the CYA level is high then one needs to lower it anyway so might as well do a partial drain/refill.

[yooper]

This ammonia problem is new to me, looking for answers. I opened my pool cover last week after it being closed for 3 hot days (near 100) and a hard rain, and water was cloudy. Although I do have an electric pool cover so I don't think the rain has anything to do with the problem. I have an inline chlorinator that uses pucks and had it set at 2 out of 8. The week before we had my son's baseball team party (about 20 swimmers) but the water was clear afterward until the following week when I opened the cover. I'm thinking the heat and low chlorine killed my water. Took a water sample to local pool dealer and had it analyzed. 0 cya, and no FC. They said I needed 157 bags of burnout 35 or drain 18" and refill. I did the drain and refill and had it tested again. This time it was 99 bags of burnout. Drained and refilled the 18" again. Not much different, 91 bags of burnout. My ph is 7.3, alk is 297 and hardness is 333. Started me with 3 doses of 1/2 gallon of muriatic acid and a quart of phosphate reducder even though the printout doesn't give a phosphate number. Just wondering if I'm getting a load of crap here and what the right remedy is for this problem.

10 year old pool
18' x 36'
Inground vinyl liner
26,000 gallons
75 gallon per min. Hayward sand filter
1.5 hp filter pump
electric cover
inline puck chlorinator

[chem geek]

Well, you really should get your own good test kit, either the Taylor K-2006 or the TFTestkits TF-100 with the latter kit having more of the reagents you use the most so is more economical.

If your CYA did drop to zero, then bacteria may have converted it into ammonia. This happened to me and yes, it does take a LOT of chlorine. You can do a bucket test using pool water to determine how much chlorine it will take. Just see how much regular 6% bleach it takes in 2 gallons of water, noting that 1/4 teaspoon is 10 ppm Free Chlorine (FC), until you start to register an FC reading. Either that, or get an ammonia test kit from a pet/fish/aquarium store and figure you'll need around 8-10 times that amount of chlorine, minimum. See It Can Happen to Anyone - Zero Chlorine, CYA --> Ammonia.

[Grant]

Very interesting discussion. Has anyone considered the use of a UV (Ultraviolet) system to reduce the amount of chlorine demand in the pool by both destroying the ammonia and deactivating the microbio in the water? I do not know if UV is an economic solution for these types of problems but for small pools, a 8 gpm system would be about $700 and for large pools, a 12 GPM UV system would be about $850.

Unfortunately I do not know the costs of chemicals, maintenace and down time (drain/fill) but maybe someone out there can tell me the annual cost to maintain a pool. UV is used in larger pools but I have only started seeing their use in smaller ones as their costs have come down significantly.

Grant

[chem geek]

A UV system isn't typically beneficial in an outdoor residential pool. Ammonia in sweat and urine gets oxidized by chlorine without difficulty and the bather load is very low in a residential pool. An outdoor pool is exposed to UV in sunlight that produces hydroxyl radicals when chlorine breaks down. UV is better used in indoor pools where there is no exposure to sunlight since it can help control chloramines while in commercial/public pools it can help because of the higher bather load (as can ozone) and can help inactivate the protozoan oocyst Cryptosporidium parvum.

[sapoolguy]

We're in S Texas, and have multiple outdoor residential pools doing just fine on UV light sanitation and just a fraction of the pool's prior chlorine consumption
http://sapoolworks.com/index.php?/blog/detail/lighten_up/