Well, one silly thing I did as Denske mentioned, was not add bottle number two to the ammonia and nitrate (nitrite?) test. I thought they were spare bottles. Reading the instructions closely helps :P I re-tested last night, and the levels were still at zero from what I can see.
I did about a 25% water change last night, and replaced with water from my kitchen's R/O filter. I tested water around lunch time today, and saw that my pH was still around the 8.4 mark, but my GH and KH dropped from 8 to 5. It seems like a big drop, or my tests were off a bit. When I tested my bucket of R/O water from the sink, the pH was around 7.0. I guess I expected some kind of pH drop in my 20 gallon shrimp tank.
I would like to get my pH down to the mid 7 range, but am a bit leery to mess around with that given my current water testing. Would something like pH Down be safe to try, or would it potentially cause a crash? I'm guessing I don't want my KH or GH to go down any further.