The first unit sent out had a bad pinch valve that was corroded and fell apart, so Neptune sent out a refurbished replacement unit. The new one tested correctly for one test, then the phosphates declined rapidly and after only 3 tests reads zero 100% of the time despite the Hanna results showing a consistent range of .05-.10. The support experience was disappointing and slow with no resolution so I have requested an RMA and will not be using this product until it is has been shown to work correctly. I hope many of you are having better experiences, and hope this can get resolved and work as effectively as the original Trident does. Please forego the complaints about Neptune and Aperture if you would be so kind in your comments, as the purpose of this post is to see if anyone out there is getting a better result than I have so far.