Every Given Sunday

One of the many great things about the NFL being back is that I have a consistent demarcation for my weekly water changes. Much to my surprise, my drop checker turned green, even a little yellow after refilling with water. I decided I had better check my parameters, to figure out what prompted the difference; the pH was 7.0-7.2, and the kH was 14 degrees.

Using the CO2 calculator, this corresponds to 26.5-42 ppm CO2. I'll call it 33 ppm, corresponding to a pH of 7.1. This is curious to me, because obviously, the CO2 rise is due to the fresh water, not the CO2 running, but I read somewhere that water suppliers try to avoid this because dissolved CO2 can be corrosive. On the other hand, maybe they just want to get the water to a neutral pH, and because it is so hard, it has to have dissolved CO2 in it. I suppose then, I shouldn't be that surprised, because I had measured the pH of the tap water rising ~1.0 when left to sit out (from 7.0 to 8.0).

I will take this to mean that the minor correction I made earlier in the week (diluting the drop checker solution with a bit of distilled water) wasn't totally out of line, and may have even gotten me to the proper Kh!