Alkalinity measures difference

[samjesse]

Hi
I just got my Clear Choice Labs yesterday and tested for TA yesterday and today, both reading gave 0. i.e. the water colour became red if you are familiar with CCL kit.
This newly purchased house came with the Aussie Gold 4 in 1 test kit which reported 100 on TA test.
2 week ago the sample to the pool shop gave 60 TA.
well. which is the correct reading? sorry to dump this on you but I am lost.

Thanks

 

[AusPhil]

I assume you mean it turns red when you put in the detection reagent in step 4,
What are all the other results? maybe they might give us a clue...

Edit PS, i'll believe the CCL kit as long as we don't pick up a testing error

From the Instructions......
1. Rinse the total alkalinity viewing tube with pool water.
2. Fill the total alkalinity viewing tube to the mark indicated (lower line).
3. Add two drops of the total alkalinity buffer, and mix well. Replace the lid on the
reagent immediately to extend the life of your kit.
Note: if your Free Chlorine (FC) level is very high, use additional total alkalinity buffer to
neutralize the FC.
4. Add four drops of the total alkalinty detection reagent and mix well. The solution should
now be green or blue. Replace the lid on the reagent immediately to extend the life of your
kit.
Note: If the solution is a red, yellow, or pink colour, then you may stop the test here, as your TA
is 0.
5. One drop at a time, add the total alkalinity titrating reagent. Mix between each drop,
and count the total number of drops added until the colour changes (usually to red, but
possibly also pink, yellow, or clear). If you are unsure whether the colour change is
complete, add one more drop – if there are no more changes, don’t count the extra drop in
your total.
6. Multiply the number of drops by 25 to get your TA level in parts per million (ppm).

 

[samjesse]

AusPhil
Yes, you are correct.
Here is the reading from yesterday using CCL kit.
Salt 6000
CC 1
FC 1.5
CYA <35 "I could still see the mark very clearly and run out of mix to add", poolshop 2 weeks ago shows 0

 

[AusPhil]

AusPhil
Yes, you are correct.
Here is the reading from yesterday using CCL kit.
Salt 6000
CC 1
FC 1.5
CYA <35 "I could still see the mark very clearly and run out of mix to add", poolshop 2 weeks ago shows 0

Hopefully the chem gurus will pop up soon but those results are concerning.
Can you detail you pool in your signature please.
I'm going to assume you are using a SWCG as your primary chlorination source though.
1. the salt level may look high to the US members but it is likely ok depending on which model swcg is being used.
2. Sydney hasn't been that hot or sunny this week so the FC/CC results show that the SWCG is failing to provide enough chlorine. undersized, too old or just can't keep up with the algae growing.... don't know yet.
3. FC/CC result indicates the start of an algae bloom even if the water is not green.
4. if your CYA is <30 you may need to raise it but by how much will depend on if you need to SLAM, pool shop may well be correct.
5. likely you do need to SLAM
6. CYA does degrade over time especially in a hot aussie summer, i personally dropped 40 to 50 ppm over summer.

 

[Costas > DownUnder]

You can simply run a TA test on the test standard (TA = 100ppm) which should have been supplied with your kit.

If you measure the standard and it is correct then you are testing correctly and I would believe the CCL kit results over the 'Aussie Gold 4 in 1' kit.

 

[samjesse]

Costas,
Thanks, after following you suggestion, I confirm that I was not reading the test instruction correctly, and the TA of the pool is 100 and not 0 as in my first post.
PS: TA standard should be 100ppm seams to be 75ppm "turned read after 3 drops and the 4th drop did not change the color much" or I am becoming color blind

 

[Costas > DownUnder]

PS: TA standard should be 100ppm seams to be 75ppm "turned read after 3 drops and the 4th drop did not change the color much" or I am becoming color blind

Probably close enough - Some variance may simply be due to how hard you happen to squeeze the reagent bottle, mixing, exactly how much solution is in the vial to start with etc etc.