My reading of the post is that the Seneye (according to posters here - I haven't heard from the company) needs to be re-calibrated for the tank its being used in - again - I don't understand the logic - so I may be quoting it incorrectly. However, the implication was that the results 'out of the box' are incorrect.28% the real concentration of ammonia or ammonium?
The seneye tests for ammonia (nh3), at reef Ph levels you would expect to see a ratio of ammonia to ammonium of ~1:3 (according to Randy's article on reef alchemy)
If you are looking for ammonium levels and got 1/3 the expected amount but in ammonia then your ammonium would be accurate. Or vice versa