Planted Tank Enthusiast
Join Date: Nov 2004
Location: Los Angeles, CA
Milwaukee pH Meter issues? Calibrating?
Oye! Today's my first monthly maintenance, so pardon the few questions I've had to post today --
On my schedule of things to do, was to calibrate my Milwaukee ph meter, a recommeded procedure once a month.
When I got the Milwaukee meter last month, I calibrating it as instructed to 7.0 with the solution that came with the kit. I hooked it up to my CO2 tank, eased in to a steady 6.7-6.8 setpoint on the meter, and have been getting consistently steady 6.7-6.8 ph readings from my Aquarium Pharmaceuticals kit. Healthy fish, pearling plants.
Well, today I went to calibrate my ph probe with some Coralide pH 7.0 calibrating solution -- this is different than the original solution I used, which remember came with the Milwaukee kit. The Coralife is brand new, not yet opened, bought about 2 months ago -- no expiration date though. I removed the probe from the water, rinsed it in a solution of Coralife, and then took a measurement in a separate solution of Coralife. The pH meter jumped and stabilized to a whopping 7.6! Still, I took the little screwdriver that came with the Milwaukee and turned the calibration knob so that it read 7.0 while dunked in the solution. I rinsed off the probe with tap, placed it back in the tank, and the reading on the meter nose dived to 6.1 (remember, previous to this calibration it read 6.7-6.8 and my test kits confirmed this)
My Aquarium Pharmaceuticals kit is testing no where NEAR 6.1. I tried calibrating the probe again with another sample from a new bottle of Coralife solution. Same result. Call me crazy, but the tank water cannot be 6.1. With my KH of 4, that would be about 90ppm of CO2. Dead fishies.
SO what gives??
1) Bad calibrating solution? What brand do you folks use? Where do you order from? Got mine from Big Al's
2) Bad probe? (Seemed on target though when calibrated originally with calibrating solution that came with meter)
Are there any houshold products -- soda? -- that I could test the pH probe that have a known pH and wouldn't harm the probe.
For know, I'm going to set the meter back where it was. But I could use some answers to help ge tback on track.