[quote author=Drew Davis link=topic=139748.msg1049786#msg1049786 date=1356836654]
Also, this is not for fish. It's for algae.
Interesting link! Glad you said it was for algae as I was surprised like Delta_G with what fish you were trying to turn into caustic soup :astonished:
If you look up aquarium controllers a lot of the pH probes are damn expensive. I'm not sure if that's just because they're made to last while continually in the tank, or also because aquarium equipment is often overpriced. Some of the well-known manufacturers recommend cleaning them at least every couple of months. Many people use undiluted white vinegar or lemon juice for this. Even then the probes only last up to 18 months or so.
As for the buffer solutions, since you're only concerned with a pH of 10-11, did you know a borax solution can be used to calibrate near this range? It will produce a buffer solution of around pH 9.2, so this method requires a controller that will allow calibration using arbitrary buffers. That Sparkfun kit doesn't do that.
I just did some searching and apparently these probes are pretty popular for the price: