Hey Bryan,
I had the same problem but with the Seachem bucket.... After many frustrated attempts I actually found out that the kit I was using was giving me wrong results. Coincidentally, it was the same one you posted in that link. I even confirmed with the standard that came with the kit. I don't know... Maybe I was doing something wrong or something. I only discovered the problem with the kit after I switched to Salinity and bought a new kit.
So, my suggestion is try to use another kit.