Something funny happened this morning...

[FnC80]

So we had our pool installed this past August and I’ve been doing TFP since inception. I test the ph and FC every other day and do a full testing gamut every Friday or Saturday.

So the odd thing is this. I grabbed a quart of pool water to test and started out with the TA test using the TF100 test kit. I add the green drops and the sample stayed bright pink. Odd I think... it usually turns green/blue. I dump it, grab another water sample from the quart of pool water and again... same result.

Now I’m thinking maybe somethings wrong with the chemical drops? So I decide to check the ph really quick using my electronic probe... it reads 3.9! Now I’m wondering what’s going on? I calibrate it monthly so I wonder if maybe it’s just really off? Though it was fine on Wednesday.

So I decide to recalibrate and low and behold it’s spot on for the calibration solution... so what gives? I dump the pool water and go grab another quart of water and everything is fine... So my question is what happened? I mean I haven’t added acid in about 2 days... being new plaster I seem to have to add acid a few times a week to keep it around 7.8. My thoughts are for some reason maybe a bit of acid didn’t mix with the cold pool water? Current temp is 59, but a whole quart? I have a vsp pump, so I run it about 18 hours a day... turn over shouldn’t be an issue.

I’m kind of at a loss of how I got these readings... I’ve tested the pool hundreds of times it seems and nothing every out of the ordinary.... ever. And all other results were fine after the second round of testing with the second sample of pool water, with a CSI of -0.01 at the moment (pool math). Any thoughts from the TFP brain trust? Thanks in advance.


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17.7k gal, 98 ft perimeter, IG quartz, 3HP EcoStar VSP, 1.5HP TriStar Dual Speed, 725 sq ft SwimClear Cartridge, Rainbow chlorinator, Paramount clear O3, Pro Logic controller, 500k BTU heater, AquaVac 500, Spillover Spa, 3 sheer waterfalls, 3 bubblers.

 

[mknauss]

Sounds like a mystery. Did the container you got the water in have acid in it recently?

 

[JamesW]

Maybe a tiny bit of acid was in the sample bottle?

 

[FnC80]

It is the container I use to measure out acid, but I always rinse it out with pool water after dosing and putting it away with the test kit. Then I rinse it again before taking my sample. Maybe I wasn’t fully awake and didn’t rinse it before I did it? But then how much acid would it take to turn a quart of water to have an acidity of 3.9? It’s likely the most plausible solution, leftover acid in container... but the tons of times I’ve done it no issues... but then it only takes one time.


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17.7k gal, 98 ft perimeter, IG quartz, 3HP EcoStar VSP, 1.5HP TriStar Dual Speed, 725 sq ft SwimClear Cartridge, Rainbow chlorinator, Paramount clear O3, Pro Logic controller, 500k BTU heater, AquaVac 500, Spillover Spa, 3 sheer waterfalls, 3 bubblers.

 

[mknauss]

You solved your mystery. It would take a drop or two of acid in that small amount of water to get the effect you described.

Take care.

 

[FnC80]

Hmmm now that I know, not quite as interesting. Of all the scenarios I came up with in my head yesterday, the simplest never occurred to me. Thanks again and Merry Christmas.


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17.7k gal, 98 ft perimeter, IG quartz, 3HP EcoStar VSP, 1.5HP TriStar Dual Speed, 725 sq ft SwimClear Cartridge, Rainbow chlorinator, Paramount clear O3, Pro Logic controller, 500k BTU heater, AquaVac 500, Spillover Spa, 3 sheer waterfalls, 3 bubblers.

 

[kimkats]

That is why I have one measuring cup to add acid (orange), another to add chlorine (clear), and a whole different one to get my sample of water to test (plastic bottle).

Just to be on the safe side.........make sure you are not storing your M. acid by the chlorine. They do not play well together. The M. acid should not be stored too close to metal as well as the fumes may cause rust. I keep mine outside behind the barn where none of the critters go.

Kim