How soon after pouring bleach can you re-test?

[callmedpit]

Just starting with the TFPC method for the first time, had to drain 50% and re-fill to get my CYA down. My chemistry was the following after the refill:

FC: 0.6
CC: 0.4
PH 7.5
TA: 70
CH: 220
CYA: 35

According to the calculator (8.25% bleach), I needed to add 1 gallon to push the FC up to 5ppm. I put a gallon in, ate dinner, etc. About an hour later I re-tested, FC was the same thing.

Am I not waiting long enough, or how long does it take before I will see results in my test?

 

[Casey]

As soon as you add Chlorine, you can test within 15-20 minutes. If you did not hit your target FC, you need more chlorine!

 

[UN1017]

There are a few possibilities:

1. You could have something in your pool that consumed it or
2. The bleach was old or
3. Your testing was off (bad reagents maybe)

I'm banking on #1

Also, it's ok to keep everything under one thread. It makes it a little easier to follow your situation. You are using a K-2006 test kit, right? Was there a particular reason you are using a 25 ml sample instead of the 10 ml for the chlorine?

 

[jblizzle]

I am not sure 15 minutes is long enough. I would circulate at least 30 minutes before testing.

 

[callmedpit]

There are a few possibilities:

1. You could have something in your pool that consumed it or
2. The bleach was old or
3. Your testing was off (bad reagents maybe)

I'm banking on #1

Also, it's ok to keep everything under one thread. It makes it a little easier to follow your situation. You are using a K-2006 test kit, right? Was there a particular reason you are using a 25 ml sample instead of the 10 ml for the chlorine?

Yup, K-2006. The 10ml does multiples of 0.5ppm, while the 25ml does multiples of 0.2ppm. I knew my FC at first was going to below 1.0ppm, so testing in multiples of 0.2ppm made more sense I would think?

 

[jmbradwell]

The 10 mL sample is more than adequate. Uses less reagent which will make your kit last a bit longer. Its all about saving money so you can afford pool toys.