Ok so I made my first garbage can full of RO
water I mixed the salt in it 24 hours ago. I took my refractometer and placed a few drops of RO
water on it and it read 0. So I figure it was calibrated just fine. I then tested my batch of fresh RO
saltwater with the refractometer and it read about 1.021 I checked it with my 2 swing arm hydromoters the red sea hydromoter(old one) read 1.016 and the brand new instant ocean hydromoter read 1.026 I was shocked at the difference in readings and am wondering if anyone understands why I could get such different readings. I am assuming to trust the refractometer. But the past 8months i have been trusting my red sea hydromoter if it is off that much I have had way too high of specific gravity the entire time I have been doing saltwater. Any thoughts???
I just tested my tank water with the refractometer it read 1.030(holy toledo) since my red sea hydromoter was off about 5 points my tank is about 5 points too high.
My refractometer is model RHS-10ATC I got it from DR Fosters&Smith