After looking at the Best Guess chart and chemgeek's charts, it seems that I should keep my CYA at around 20 so I don't need to have FC above 3 or 4. Because of a slow leak, I do lose CYA over time, so I've been alternating using bleach and trichlor, depending on my CYA level.

What's the best CYA test out there? I have a Taylor kit with the "little black dot" test, but this seems highly subjective. Also, the results can vary depending on the amount of ambient light, direction of the light, etc. Plus 20ppm is at the very limit of the test's scale. I also bought an AquaChem strip test, but its results are more like rough estimates than anything else.

Are there any better tests out there for CYA?