Well... I finally able to test my refractometer with a new solution.
But 1st I calibrated again with Brightwell solution that I have been using to 35ppt.
Then I dropped the new solution by Aqua Craft.
Showing 37ppt. Dun dun dun....
Which one should I trust???
But I tend to trust this new solution... Cause everytime I tested my alkalinity on a new mixed Tropic Marin Pro reef saltwater, its showing 6.4 or lower..
And my apex conductivity is showing 32.7
I calibrated the refractometer with the new solution and tested my tank water....
Yup it is 33ppt.
So.. I have been mixing my saltwater lower than I want it...
Finally my alkalinity issue with this tank is answered.
Stupid brightwell solutions..