Swing Arm Hydrometer Users

nm reef

Active Member
Very interesting calculator....but I've been using three swing arms since about the 3 month mark of my reef...and I have a source with a high dollar refractometer that compares my swing arm results to his refractometer and my results are always very close to his. According to the calculator you provided my SG is actually 1.0264 and not 1.024 at 80 degrees. I wonder why the refractometer used to validate my swing arms says my numbers are closer to accurate?:cool:
 

squidd

Active Member
The Link says "Most" hydrometers are calibrated at 60 f ,That's true for the one I use in Auto shop and probably most "lab" grade units...But My Aquarium Rated swing arm is calibrated at 75 f, so the difference at 78 f is MUCH less..
I also have a buddy that spent the "Big Bucks" for a refrato meter and an electrical monitor. So I've gone over with my unit to get it "Calibrated/Checked" and the difference is minor and noted and "Consistent"
So now I KNOW what my unit measures.
:cool:
 

dacia

Active Member
According to this website, when I performed hyposalinity I did it at 1.0125. I wonder how many people out there are going to this calculator with their hydrometers, and are actually adjusting their salinity according to the measurements they receive there?
 

reefnut

Active Member

I wonder how many people out there are going to this calculator with their hydrometers, and are actually adjusting their salinity according to the measurements they receive there?

I know the guy who gave me the site is... I'm going to let him know he needs to confirm his readings with a refractometer. I wish there was a way for me to... One of these days I'll get me one.
 

beth

Administrator
Staff member

Originally posted by Dacia
According to this website, when I performed hyposalinity I did it at 1.0125. I wonder how many people out there are going to this calculator with their hydrometers, and are actually adjusting their salinity according to the measurements they receive there?

This is the point EXACTLY. No one thinks about this, knows about this. Generally, folks go into the LFS and get a swingarm thinking that they are getting something that is going to be accurate and safe. Wrong. They are off to a degree that even using them to measure salinity level in your tank is near useless if you are concerned about animal health. With refracts going for around $50 at ----, there seems little reason not to get one if you plan to be a hobbyist longterm.
 
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