Chlorine staying up

[Iowark]

Hello all,

I am new to the pool scene and have a question.

Our pool builder put too much CYA (110 ppm) at the start up and we had trouble holding chlorine and the pool turned milky. We drained down to get the CYA down and to try to get the pool balanced.

I have not had the opportunity to get lab readings, but I did a few tests of our own.

CYA: ~50-45 ppm
FC: 15
CC: 0

Since the plaster is fairly new he said not to bother testing for Alk for over a year. I am skeptical. We have a blue stained plaster.

Our chlorine after refill was over over 20, but dropped to 15 ppm and has stayed there over a week with out additional chlorine (tab feeder is off). We have had 90 degree sunny days.

Every time I check I have to add about 2 cups of MA which I understand is common with 3 month old plaster.

I have a separate question about the Taylor ph test in the TF_100 kit. Does it have anything to neutralize the chlorine? Our other test kit does and maybe I haven't taken the time to find it in this kit.

Thank you in advance.

Bobby Sullivan

 

[JasonLion]

With new plaster, you should not normally adjust either TA or CH for the first six to eight weeks after the plaster was applied. After that it is good to test and adjust the levels more or less normally, keeping in mind that TA and CH will both continue to rise slowly from the plaster curing for up to a year.

With CYA over 100 you might not be able to tell if FC was falling, but with CYA around 50 you should be losing at least 30% of your FC level each sunny day, and probably more.

There isn't any separate chlorine neutralizer, it is already included. The Taylor PH test is fine for FC levels up to 10, and is only off a little for FC levels up to perhaps 15 or a bit more.

 

[PaulR]

There isn't any separate chlorine neutralizer, it is already included. The Taylor PH test is fine for FC levels up to 10, and is only off a little for FC levels up to perhaps 15 or a bit more.

Would a drop of R-0007 (thiosulfate) help for higher FC levels?
--paulr

 

[JasonLion]

Not really. Everything that thiosulfate can help with has already been done in the Taylor PH reagent. Adding thiosulfate shifts the PH at the same time that in neutralizes the FC, so you throw the results off in a different, but not really better, way than FC alone does

 

[Iowark]

Back from the lab!

Pool Chem store readings:
FC: 5 ppm (only reads to 5ppm)
TC: 5 ppm
pH: 7.8
CH: 255 ppm
TA: 95 ppm
CYA: 100 ppm (I looked through the vile and thought it was lower, they have a 100 bar and 50 bar)
TDS: 600 ppm

Pool Builder Lab using Bioguard test strip reader (skeptical)
FC: 4.2
TC: 5
CC: .8 ppm
pH: 7.5
TA: 55
adj TA: 27
CH: 291
CYA: 93
TDS: 300 ppm

TF100 measurements:

FC: 7
CC: 0
TC: 7
pH: 7.8
TA: 90
CH: 280
CYA: 50

Temp: 84 degrees

Why would the CYA acid readings be so different? Call me confused. I have a science background, so I feel confident in my test procedures. Advice on which to trust? I match the Chem store besides CYA.

Regards,
Bobby

 

[JasonLion]

Trust your own results!

The CYA test is a little tricky until you get used to it. The results also vary depending on lighting. It is designed to be done outside with the sample shaded from direct sunlight. You tend to get higher readings indoors.

The most important thing is to get consistent results. Doing the testing yourself is the best way to do that.

 

[Butterfly]

Hi Bobby and welcome to the forum

You got the TF100 and I absolutely agree that you should trust your own testing! :-D

Just to help you get a visual on the CYA test, here's a link to Taylor:

http://www.taylortechnologies.com/Chemi ... ntentID=44