OK, I measured 1.2 gr of silica and added it, after mixing it in a cup of reservoir water. According to Moe's formula, 10gr sil x 30 ml ph down, I should need 3.6ml of pH down. I'm using GH down, so let's start with 1ml pH down. Waited a few minutes to allow it to mix and circulate, measured pH with my
Bluelab pH pen, it's 8.2. Add 1ml more, wait, test. PH was at 5.9. Hmmm. 2ml is a long way from 3.6ml???
Enter the new 6in1 water meters from China I have now that I want to use for monitoring the water. I calibrated them as well as my
bluelab pen last night and all were reading correctly in their respective calibration solution. 4.0, 6.86, 9.18 for the 'white' China monitor and 4.0, 7.0, for the
Bluelab and 'green' faced China monitor. I took about a hour to get everything installed in the reservoir and in the mean time, the pH rose slightly, according to the
Bluelab pen.
Well, like I said, the
Bluelab was reading 5.9, it has since risen to 6.1. The green is reading 7.26 and white faced is 6.55. Life is soooo fun some days.

Should I start a poll to see which meter gets the most votes???

...and all three were reading correctly in the calibration solutions!
All I've had to use for pH measurment, until yesterday, was my
Bluelab, but whenever I used a receipe like Moe's, it seems to always read lower than expected! Hmmm??? I don't even want to think how low the pH would be if I added the additional 1.6ml of pH down. ??????
Why? the green and
Bluelab were exactly the same in both the 4.0 and 7.0 solutions. Put them into the reservoir and they're 1.1-1.2 differant. What is up with that??? I'm so confused.... I need a dab, no, make that a blob. hehehehe
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