reefer newby
Active Member
I am going to purchase a tds meter. I have been researching and I see there is a 1000 and a 342 calibration liquid. Which one do I get? I will probably get an him handheld unit , if that tells you anything.
calibrating a tds meter
- Thread starter reefer newby
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They don't need to be calibrated, you could get a fluid to test the accuracy of the meter...if you do use the 3xx one. But like I said, they come calibrated.
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ReeferBob
Valuable Member
I use RO water and they do need to be calibrated every once in awhile. They might come calibrated but usually they are off. Some people will tell you to use the calibration fluid but the RO water is fine. Put a drop on and move the line to "0".
jduck
Well-Known Member
most likely you need the 342 solution. Most brand new ones come calibrated from factory.
Immerse the meter into the calibration solution. If the meter does not read within 2% of the calibration solution, adjust the reading by either digital calibration (for some products) or inserting a mini screwdriver into the trimmer pot (the hole on the back of the meter). Turn the trimmer clockwise to increase the reading and counterclockwise to decrease the reading. Note that the adjuster is very sensitive. Always refer to the calibration instructions for your particular product.
2% error is the better type on 342 solution is 6.8 tds. Some of the ones are 3% error
Immerse the meter into the calibration solution. If the meter does not read within 2% of the calibration solution, adjust the reading by either digital calibration (for some products) or inserting a mini screwdriver into the trimmer pot (the hole on the back of the meter). Turn the trimmer clockwise to increase the reading and counterclockwise to decrease the reading. Note that the adjuster is very sensitive. Always refer to the calibration instructions for your particular product.
2% error is the better type on 342 solution is 6.8 tds. Some of the ones are 3% error
The HM Digital handheld TDS-3, TDS-4TM and their new AP series are hard to beat for the price, usually $20-$25 at many RO vendors. If you buy on ebay be very careful, there are imported clones which appear identical but are going for around $9 and they are not the same meter or quality.
The advantages of those I mentioned are they are ATC or temperature compensated while the inlines are not, and can be used portable to test most any water source other than saltwater which is way above their range and again inlines cannot be used portable.
For calibration you want to use a solution closer to the range you will be testing so the 1000 is too high, the 342 solution is more in range with most tap water TDS. The biggest key to TDS meter life and accuracy is to triple rinse the meter in RO/DI water after each use then put it away clean and with the cap on it so it stays that way. Never dip it in saltwater as the TDS of that is somewhere over 32,000 and the meter only goes to 999 on most in low range and some do 9,990 by tens in high range if they are dual range.
The advantages of those I mentioned are they are ATC or temperature compensated while the inlines are not, and can be used portable to test most any water source other than saltwater which is way above their range and again inlines cannot be used portable.
For calibration you want to use a solution closer to the range you will be testing so the 1000 is too high, the 342 solution is more in range with most tap water TDS. The biggest key to TDS meter life and accuracy is to triple rinse the meter in RO/DI water after each use then put it away clean and with the cap on it so it stays that way. Never dip it in saltwater as the TDS of that is somewhere over 32,000 and the meter only goes to 999 on most in low range and some do 9,990 by tens in high range if they are dual range.
ReeferBob
Valuable Member
Doh! what the heck was I thinking? thanks lol!
