AWT test results


New member
I decided to have AWT (Aquarium Water Testing ) test my water so that I can compare their results against mine.Out of all parameters tested, there are two elements with HUGE concentration discrepancies. The first is Phosphate. Their results indicate a concentration of 0.21 whereas mine reads 0.02 with a Hanna meter. I have an SPS system and I would think that at .21 I would not only have mostly brown SPS with little or no growth, but a system full of algae as well. The second discrepancy is in the Ca concentration. Their results indicate 280ppm and mine is 460ppm tested with API. Again a big difference!My question is what can I trust? Can salt water samples somehow shift concentration of elements during shipping?? My corals have good growth and color and very, very little algae in my tank so not sure what to do here??? Perhaps both, my Hanna and API tests are faulty?

Please advise and thanks in advance!