Guys - I just received my ATI ICP test back and it shows my salinity at 31.7 or 1.0239sg. This is the second of three I sent that shows low salinity. I am using three sources to check my salinity and I can't figure out why ATI is showing it so low. I am using my APEX, Hanna Salinity Tester (just calibrated again) and two hand held refractometers. Each time I use the refractometers I calibrate them with RO water. If I use the handheld refractometer I read 35sg but when I use the Hanna tester I get 33sg. The Hanna tester is much closer to the ATI ICP test. I am having SPS issues with little to no polyp extension so I am wondering if the ICP is accurate. Anyone else using ATI for their ICP test and get wierd salinity readings or are my refractometers (1yr old & 1 week) old trash?