Sure enough, 2 ppm ammonia

[rapfeifer]

It happened to me! In two days of light usage our CYA went from 80 ppm with crystal clear water to zero with severely milky water. No green algae, no apparent algae at all. We've been trying for 10 days to figure out what happened. Our local pool guy really didn't have a clue. He recommended we use a non chlorine shock every other day until CYA came back up....I did that 5 times with absolutely no change.

Then I found this forum and chem geek's description of his problem. Went to the big box, got an ammonia test kit, and sure enough, 2 ppm ammonia.... So now we're superchlorinating until it will hold. Took it up to 35 ppm (based on amount required for superchlorination with 3.5 CC) and it went to zero FC in 30 min. We did get that "pool smell" - chloramines! So I take that to mean that the ammonia is reacting with liquid chlorine and eventually we will be burning it off with the chlorination. So we'll do what we can tonight by repeatedly adding shock levels of chlorine and watching it come down. Water is clear, all other chemistry seems in line - just no FC and apparently no remaining CYA.

Complicating factor is we are leaving for four days tomorrow. Should we keep the chlorinator running full steam while we are gone? Any other recommendations? When should I put some CYA in again?

I thank chem geek for the blow by blow!! It gives us an idea of what to expect. :? (Looks like we have "the worst case where there (...is...) ammonia, then the rule you can use is that it takes up to 2.5x the CYA drop as FC to clear it. If it were a 40 ppm drop, then that would be 100 ppm FC. " (chem geek, May 20, this year) Since we went from 80 ppm CYA to zero, we may be looking at 200 ppm FC to get rid of ammonia....in a 30K gallon pool...ouch.)

 

[chem geek]

Re: It Can Happen to Anyone - Zero Chlorine, CYA-->Ammonia

Welcome to TFP! Sorry you had to come here with such a bad experience, but glad we're able to help out. I certainly hope you don't have a "worst case" situation. If it was like mine, you might be looking at more like around double the "expected" amount needed to get rid of the ammonia, so around 30-40 ppm FC cumulative. At any rate, it'll take whatever it does and you know how to do it.

When you say run the chlorinator, are you talking about an inline chlorinator that uses Trichlor tabs? I suppose since your CYA is gone that you could certainly use those. My worry would be that you could end up with the cloudy mess turning into algae -- in fact, it's likely that the cloudiness is in fact nascent algae growth (algae love ammonia as a great source of nitrogen; better than nitrates for many of them).

Worst case, you'll come back to algae that you'll need to shock to get rid of anyway. The only problem with that is that it could take even more chlorine. Not sure what you could do unless you can get someone else to feed the chlorine-eating monster.

By the way, how did this happen in the first place? Usually, the FC would have to get near zero in order for the bacteria to be able to survive. Maybe algae started to grow (because the FC was below 4 ppm FC or so) and got the FC down to zero...

Richard

 

[rapfeifer]

Re: It Can Happen to Anyone - Zero Chlorine, CYA-->Ammonia

Well, we left the inline chlorinator (trichlor tablets) running at our usual maintenance level while we were gone five days...came back home to a nearly clear pool. (Not crystal clear, but barely hazy in the deep end.) BUT - A ittle algae had started to grow. FC values zero... CYA values about what would be expected after last week's addition ~15 pm. Ammonia values zero

Added another 15 ppm liquid chlorine last night to get rid of the algae and continue our work on the problem.

This afternoon took the sample for analysis - zero FC, 0.4 TC, 16 ppm CYA. Phosphates very low... Alkalinity a bit low (108) and pH a bit high, so added alkalinity plus and then muratic acid to correct those.

A few hours later, used 5 # DyChlor to get some chlorine (and a bit of CYA) back in the system. Will test in a couple of hours to see if we have FC. Plan to add algaecide and phosphate remover later tonight.

Will do an in depth test again tomorrow to see where we are. Probably keep pouring in the liquid chlorine to a 10-15 ppm level until it holds overnight. Will need to add CYA again sometime - but my pool guy still thinks the CYA is "hiding" somewhere and when we do the right thing (don't really know what that is), it will reappear... The ammonia test pretty much convinced me that that will probably NOT happen....

Based on my addition of DyChlor, the CYA levels should be a bit higher when we test tomorrow. We'll see!


Side note - Don't know how it happened. Pool was about 87 F, chemistry balanced, and covered for a couple of days, nothing unusual for us. Chlorinator had been running (and had tabs), nothing different from most other summers, it seemed like....

 

[reebok]

Re: It Can Happen to Anyone - Zero Chlorine, CYA-->Ammonia

why are you adding algaecide and phosphate remover? because you keep letting your fc levels get to 0? you're kind of halfway doing two methods that don't complement each other.

 

[chem geek]

Well, using tabs and having the CYA at 80 ppm then it's pretty clear what happened. The FC probably got below 4 ppm FC or so and the algae grew faster than chlorine could kill it and then really dropped the FC even lower quickly. Then bacteria grew and consumed the CYA turning it into ammonia. This latter step doesn't always happen, but the algae growth is rather common when using Trichlor pucks/tabs if you aren't using a supplemental and extra cost product such as an algaecide used weekly.

In past summers, you just got lucky, or perhaps had a lower CYA level.

 

[rapfeifer]

We do regularly use phosphate remover, as we have had phosphate problems in the past - if you think ammonia uses chlorine, try to beat phosphate. :x Much cheaper to do prevention... I put in algaecide because we had visible algae growth and the chlorine levels weren't staying high enough long enough to do anything.

The CYA level was higher than we've had before. Normally we keep it about 50 ppm, had no idea that a little more (80 ppm) could cause such an issue. Still don't know all the nuances of what happened, but chem geek probably has it pretty close.

It held chlorine overnight, so I think we are about back to normal now. We did get two inches of rain today, so that will likely throw the balance off a bit, but the ammonia/chlorine/CYA problem seems to be solved. I'll do an analysis tomorrow to make sure.

Thanks for all the help!

 

[frustratedpoolmom]

We do regularly use phosphate remover, as we have had phosphate problems in the past -

Phosphates are algae food, but are irrelevant in a properly chlorinated pool. Pool stores like to tell people they have a "phosphate problem" so that they can sell them expensive products like "Phosfree" which are huge moneymakers for the pool stores. Our site admin had phosphates levels over 1000 and doesn't get algae, because he maintains his FC levels.

 

[JasonLion]

Phosphate is almost never an issue. My phosphate level is around 4,000 and my water is crystal clear and requires almost no effort and just the typical amounts of chlorine to maintain. We have high phosphate levels in our tap water, so there is really no avoiding it.

Pool stores are happy to mislead people about phosphates, when really their problems are because of something else (usually high CYA levels). Phosphate remover is expensive, can cause problems, and really only helps if you are not maintaining the FC level properly. It is much simpler and less expensive to just maintain the correct FC level.

 

[chem geek]

I have 2000-3000 ppb phosphates in my pool and except for when I stupidly let the chlorine get to zero and had the bacteria CYA--->ammonia problem, my pool has been trouble free ever since I ditched the Trichlor tabs (and resulting high CYA levels). My fill water has 300-500 ppb phosphates and I get blown in fertilized soil on occasion. The bottom line is that phosphates do not directly consume chlorine in any way. They merely let algae grow IF the chlorine level isn't high enough relative to CYA and it is the algae growth, even if not yet visible, that appears as a high chlorine demand.

Richard