Previously Asked Questions

• by Jason M on January 16, 2013, @9:48 PM

  Hi just purchased this to replace my hand held one. However it doesnt appear that they readings on the HM are accurate. My handheld shows a read of 3PPM after the DI stage, yet the HM unit shows a read of 0PPM. This is a little perplexing as a reefer I am trying to put 0TDS water into my reef not 3TDS... I know the unit can be calibrated but I mean I just purchased it and the claim is made that it is already calibrated at the factory. I have checked the orientation of the probes and no luck I can even use the probes to check the same water in a sterile container and still I get different readings. I know the unit is designed for moving water but still 3TDS is kind of stressful. What am I doing wrong or what should I change?

  Bulk Reef Supply Hey Jason,
  
  Both types of meters are highly accurate and come calibrated, but the inline meter will almost always be more reliable (or perhaps the better phrase is it will have the least chance of error). The difference isn't so much in the meters themselves, but rather in the process. A handheld meter will always test water that has been more exposed (as it has to be out of the unit to test it). DI water is a great solvent, if there is any amount of salt, soap residue, dust etc in the cup the DI water will pretty much instantly dissolve some of it and you will get a TDS reading out of it. It might even dissolve a small amount of the storage container itself. The inline meter removes this potential for error from the process and is why they are generally more preferred.
  

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