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View Full Version : Hanna TDS meters- good or bad?


davocean
01/13/2007, 09:14 PM
Anyone use these?
Are they accurate?

AZDesertRat
01/14/2007, 09:51 AM
They are fine. I use an HM-Digital COM-100 myself and they are not in its league but they are about as good as any other.

davocean
01/14/2007, 10:07 AM
Last night I tested a 5g and it showed 33.
I wanted to top off, and water was a little cold, so I heated up a little, then tested that same 5g and it tested at 40-41

AZDesertRat
01/14/2007, 10:15 AM
Temperature affects conductivity or TDS readings. The meters probe must be the same temperature as the water so you have to leave it in the water long enough for it to stabilize. Always use a clean glass drinking water glass to test in, do not test out of a tank, bucket etc. You will get readings fro everything that has ever been in the bucket before and was not rinsed out. Take a water glass and polish it perfectly until there is not soap residue or water spots for best accuracy.
First test your tap water TDS, triple rinse the glass with DI water, test the RO only without DI, again triple rinse and finally test the DI and final rinse both the glass and the meter so it is clean for the next use. Never store either dirty and never try to test the TDS in your aquarium, it is way above the range of the meter and can contaminate a probe quickly.
Your RO only water should be 96 to 98% less TDS than the tap water depending on what membrane you have. DI should be 0 TDS.

davocean
01/14/2007, 10:49 AM
Thanks AZ.