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Originally Posted by hunggi74
I bought a BRS 5 stage unit with built in TDS meter about two months ago. Ill get a handheld TDS unit too I guess... The amount if swing I'm seeing in calibration almost makes the unit is busted.
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The built in TDS meter can be calibrated as well. I'm not sure if J&L carries TDS calibration fluid or not - it's not listed on their website. You can use 442 ppm solution or standard 342 ppm solution, both are NaCl (Sodium chloride). Again, using distilled water or RO/DI isn't the best option as you can't tell very easily if your meter is adjusted too low in which case you would get a false "0" reading.
Calibrating inline TDS meters sucks. The meters are designed to be calibrated using moving fluid. They will not calibrate accurately otherwise. Another tidbit many people don't know. That's why I stick to my trusty handheld TDS meter.
I will check my inline meters by collecting fluid just after the inline meter then use my calibrated handheld meter in a cup to measure. Then I adjust the inline meter while it is running to match what I measured on the handheld. It's not a perfect technique, but it's good for "eye-balling" when on the lookout for problems in the system. I still rely on the handheld meter as my "final say".
Straight from HM Digital, DM-1 and DM-2 calibration technique:
http://www.filterwater.com/docs/hmdi...alibration.pdf
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Ill take it to J&L and see if they can't calibrate it. Ill also get some calibration fluid from them. Funny, it was them that told me just to use bottled water to calibrate instead of the calibration fluid...
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I'm glad to see they finally carry refractometer calibration fluid. I don't know if they use it themselves, but they used to just use distilled water. It's a terrible habit, and most people who say it's ok don't understand why it's not ok.