Total Alkalinity and Chlorine

[jonathan8610]

I just received my Taylor K-2006 kit in the mail and was doing some water tests this afternoon. Before receiving the kit, I added alkalinity increaser and shocked the pool using some results from Leslie's (not optimal, but needed something as a basis before my test kit came in). When I received my kit, I performed a FC, CC and CYA test before moving on to the TA test, but my sample goes from green to clear and then does not turn red (even at an extremely high dose of the reagant, probably around 30 drops worth). My question is, is a high FC reading (21 ppm) causing an error in the TA test or is my TA really that high? Leslie's said that my TA was 70 so I added 5 LBs of Alkalinity Increaser. My pH was 7.2 prior to shocking the pool as I know those tests are unreliable at high chlorine levels.

Test Results:
FC - 21
CC - 1
pH - 7.2
TA - ?
CH - 70
CYA - 70

 

[mknauss]

From Total Alkalinity - Trouble Free Pool
Continue adding drops until the color changes to something more or less red, pink, yellow, or clear. The sample may switch between green, blue, and gray while you are adding drops. That is not the color change you are waiting for.

 

[jonathan8610]

So clear is an acceptable color change? It went from green to clear but not red. So I should just use the number of drops to go from green to clear?

 

[IceShadow]

So clear is an acceptable color change? It went from green to clear but not red. So I should just use the number of drops to go from green to clear?

At 21FC the test can bleach out. Clear is a color change too so you should be fine to count that.

 

[mknauss]

So I should just use the number of drops to go from green to clear?

Correct. What does that make the TA?

 

[jonathan8610]

Correct. What does that make the TA?

140. I have a Vinyl Above Ground Pool. Should I lower the amount of TA?

 

[mknauss]

It will come down as you keep the pH in the 7's.