01-08-2011, 10:18 AM
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Originally Posted by chimera779
I have hydrometer and its been saying my specific gravity levels are 1.025 Which is fine with me so i left it at that for a week or 2 and now i borrowed a refractometer from a friend and it read 1.018!!! So this whole time i been thinking the hydrometer is correct. But how could the refractometer be wrong?? So which one is more correct i need help soon thanks!
optical refractrometers are more accurate than swing arm hydrometerss but thats no to say the swing arm isn't any good!. To use the swing arm make sure there are no tiny (and i mean tiny, so look closely) bubbles on the swing arm. You also need to clean it with fresh water after every use otherwise salt will eventually stick to the arm. When i use to use a swing arm i would use a tooth pick and tap/scrape the arm to get rid of any tiny bubbles on the arm when measuring the salinity. Usually after doing this you'll record a different measurement before and after that process. however, the best way to measure salinity is to use the optical version but make sure you clean the glass with fresh water otherwise salt buildup will occur there too
Last edited by reefsahoy; 01-08-2011 at 10:28 AM..