CYA change after adding salt?

[jcichocki]

I ran a complete set of numbers last weekend. On Tuesday, I added 300# salt to my pool. I had my wife run a set of numbers this morning. The CYA was half. Is that possible? Temp 88-91. Indoor. Salinity 1510 by Aqua check strip.

4/27 or 4/28 5/4

FC 5 FC 5
TC 5 TC 5
pH 7.2 pH 7.2
Alk 210 Alk 180-190
CH 430 CH 370
CYA 60 CYA 30

 

[JasonLion]

The CYA level didn't change. The test is kind of subjective. You want to keep adding solution till the black dot completely disappears. There are pictures of how it should look here.

On TA & CH, once the color starts to change you want to keep adding drops as long as the color continues changing. If you add a drop and the color doesn't change any further then don't count that drop. The CH test also requires through swirling to mix after each drop.