My Deepsix was off at 6 months. I thought I was at 1.025 and I was really at 1.029! Everthing seemed fine but it took a long adjustment to get it down. I marked my Deepsix with the correct reading I still use it now
Sometimes the swing arm is quicker in a pinch. Just calibrate it with the refractometer on occasion.
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,