If you do the TA test and the sample turns red immediately upon addition of reagent R-0008, then the TA is zero, or below.

To get an idea of how low the TA is, use reagent R-0006 (base demand) to titrate the color from red to green. Multiply the number of drops by 6.3 to get how negative the TA is.

Note: Base demand is not a very useful test for people who keep their chemistry within normal ranges. Therefore, many kits don't include a base demand test. Base demand can be helpful in some unusual circumstances, such as if the pH is very low or TA is zero, or less.

Even in those circumstances, base demand can be more trouble than it's worth. It's usually best to add a little bit of adjusting chemical and retest instead of using a base demand. This post is in the Deep End because it really won't apply to most people.