Dealing with Ammonia

[440dodge440]

There were recommendations in another active thread about how to deal with ammonia upon opening. I didn't want to hijack the thread, so I'll start a new one. The recommendation was as follows:

Treatment for Ammonia:
1. Begin a SLAM and dose FC up to SLAM level. Do not add additional CYA at this point.
2. Retest FC at 10-minute intervals.
a. If FC loss is greater than 50%, add FC to bring back up to SLAM level and continue retesting FC @ 10-minute intervals.
b. IF FC loss is 50% or less, add FC to bring back up to SLAM level. Go to Step 3.
3. If CYA is below 30 ppm, add enough CYA to bring level up to 30 ppm.
4. Continue SLAM as directed in the SLAM article until the SLAM Criteria of Done are met. Test as directed in the SLAM article - no longer need to test FC at 10 minute increments at this point.

My question is, if the water has 0 FC & no measurable CYA, what is the recommended FC level referred to in step 1? The CYA/FC chart only goes down to 20....should the CYA be added to bring the level to at least 20 and SLAM from there?

 

[Donldson]

If you had CYA in the water when you closed and open to zero CYA reading don't add any CYA to the water. The bacteria that converted the CYA to ammonia is likely still present in the water and will get to work right away converting the CYA you add to even more ammonia.

You want to perform the steps you indicated with a SLAM level of 10 ppm. Once you have finished step 2 then you have eliminated the ammonia and gotten the FC level high enough to be reasonably sure that the bacteria has been destroyed. At that point you can add 30 ppm of CYA and continue the SLAM as normal. It is very unusual to have any CYA remaining after an ammonia conversion, the bacteria involved seems to be very good at consuming it. The only cases I recall seeing it have involved either insanely high closing CYA (500+) or catching the problem right away. If you open and can't measure CYA, treat it like zero and follow the procedure.

 

[Richard320]

Shock level for zero CYA is 10 FC.

 

[Texas Splash]

Good point. I've already updated my Step 1 info:

1. Begin a SLAM and dose FC up to SLAM level. If your CYA test is showing as zero (perhaps already converted to ammonia), use a SLAM/Shock FC of 10. Do not add additional CYA at this point.

 

[440dodge440]

Thanks everyone for the clarification

 

[MarianParoo]

Let us know how it goes! p.s. I hope you didn't already add the CYA.

 

[440dodge440]

This question occurred to me only because I saw the instructions for dealing with ammonia in another post. I had this problems last year (first season with a pool, former owners closed the pool too early). I'm not sure if I'll have this problem or not this year- I hope not since I followed TFP recommendations for closing, but I wanted to know in case.

 

[Swampwoman]

Dodge, and Texas, just so you know, the ammonia "test" sequence is only usually called for if the following two conditions are present:
1. FC has gone to Zero AND
2. CYA has also gone to zero (and there was previously eg efore closing, a cya reading)

Generally, it takes at least these two conditions combined, plus sometimes debris, to get to an ammonia condition.

Texas, that's likely why the member who wrote the instructions (was it you, Donaldson, on that guide thread last year?) didn't refer to a cya level -- b/c there wouldn't be one if the conditions for ammonia were present

 

[Donldson]

I helped collaborate with the group, but I think the credit for the initial outline goes to BoDarville. While it is technically possible to catch it before CYA goes to zero, it is so unlikely that it shouldn't even be brought up so as not to confuse a new person. Remember that this can happen in clear water too, though a swamp is more likely. Follow what the test results tell you: lost CYA, low FC, high CC = possible ammonia case.

This is another reason the FAS-DPD test is so important. You can't hold FC with ammonia but it causes a sharp CC spike. With an OTO test adding 10 ppm of chlorine and retesting will still result in a TC reading of >5. The only way to properly diagnose and treat an ammonia conversion is with accurate FC and CC readings.

From my HTC One via Tapatalk

 

[Sinkhole]

Good point. I've already updated my Step 1 info:

Texas Splash,

I know this is an old post but can you put up or provide me a link to the procedure?