Aggie, Dave:

The OTO test kit in the PS-233 and 234 is for quick testing and pH. Use it instead of the FAS-DPD test for your own testing to let you know if there's a problem or you're OK, but it's pointless to use it for posting your test results--just adds to the confusion--just FC and CC are necessary anyway. TC is for only one number or when you have FC and TC to compute CC. When using Ben's kit, I suggest you use either OTO for TC, or FAS-DPD for FC and CC, but not both.

I use the PS-200 for a quick test when I'm in a rush. But if I need to ask "What's going on in my pool?" I'll only use the pH test and take the FAS-DPD test.