I did a diy version of the sps kit. Imho it works pretty well. Keeps me in a .2-3ppt swing throughout the day.I agree. I have had great results with the Hanna meter but my Apex salinity probe is all over the place.
Have you heard of the SPS? It's a salinity probe stability kit. It sends water through it constantly eliminating bubbles, etc. I have one on hand and plan on installing it this weekend. I will update afterwards. Seems promising though.
Salinity Probe Stability Kit (SPS)
Monitoring salinity in an aquarium can be a challenge-- small bubbles and debris can interfere with your conductivity probe, leading to inconsistent and unreliable results.Vivid Creative Aquatics has tackled this problem head on with their Salinity Probe Stability Kit. The "SPS" Kit is carefully...www.bulkreefsupply.com
I just use some silicone hose connected to a 50gph pump.