Originally Posted by oldpunk78
Over the years, how much do you think you've spent on probes, calibration solution, and what not. How much time invested in maintenance? Just curious.
Not much. I use the pH controller as a tool, not as an analytical instrument. I'm not so interested in what the "pH" of my water is according to the pH meter (because if I were, I'd have to calibrate at least every week, if not more frequently). More of a relative position from CO2 "off" to CO2 "on" As is, I calibrate about every 6 months. I've replaced 3 pH probes in 5 years. If they continue to calibrate, correctly and I don't see a noticeable drop, I keep using them (despite the conventional widom that you should replace them every 6-12 months).
I set my "pH" point to what my fish can handle, not what a chart tells me. This is why I like pH controllers because they allow you to easily make incremental changes versus a needle valve (or a $200 metering valve).
So, maybe $40 in pH probes (ebay), maybe $10 on calibration solution (don't buy it from an aquarium supply retailer), and probably maybe 2 hours over 5 years changing out/calibrating pH probes.