Ugh, Red Sea.
One way or the other you have to do a second opinion test on your water and match up the numbers.
Maybe a fellow reefer close by or a LFS.
I use hanna for ALK and PO4 and RS for Cal. Hanna Checkers® HC (Handheld Colorimeters)
I test ALK everyday and PO4 and Cal every 10 days.
All the rest get tested once a month by Triton US.
ok I did a 5 gallon water change today and my dkh was down from 12.6 to 12.0 so next Friday im going to do a 10 gallon water change but what im really worried about is my flow I have a hydor 1500 and a hydor 1150 on my tank