Regardless of what tool you use it should give a consistent reading no matter what. For this reading I have to give the Hanna Pen a huge fail. I have not tried the TDS pen but if it can be skewed by the electronics in our tanks I would be hesitant to use that one too.The Hanna one is a ec salinitymeter too. Like a high range tds pen and the converts that to salinity. I don't like that one.
The TM and NISupply tools have both given me consistent and repeatable reading's that can be cross checked by one another. This makes me more confident that the 2 tools are giving very consistent and accurate readings. They always agree, regardless of the fact that they are 2 different types of test.
