I have both but recently started using the refractometer more often they are both nowhere near each other in readings, the Refractometer is reading 1.020 and the Hydrometer is reading 1.025..??Which should I go with they are both cleaned and the Refractometer was calibrated and double checked???
Refractometer or Hydrometer ..??
- Thread starter Malibu361
- Start date
For me it depends on how the refractometer was calibrated. If you used a calibration solution that calibrates it to 1.025, I would trust the refractometer. On the other hand, if you calibrated it with distilled water, the refractometer is probably off and I would trust the hydrometer and would properly calibrate the refractometer.
- Location
- Brooklyn, NY
No you should calibrate it properly with a reference standard.
http://reefkeeping.com/issues/2004-06/rhf/index.php
http://reefkeeping.com/issues/2004-06/rhf/index.php
- Location
- Greenpoint Brooklyn, NY
If you calibrated your refractometer off of your hydrometer, and the hydrometer is wrong, that means your refractometer will also be wrong. :tub:
Read Pratts link. it explains it well =0)
Read Pratts link. it explains it well =0)
- Location
- Melville, NY
Get yourself the pinpoint calibration fluid, its like $4 or something, and it calibrates your refractometer to 35ppm salinity(1.026 sg).
The problem with hydrometers is that they are temperature sensitive (they work on the principal of water density and water density changes with temperature) and they are usually made to be accurate at 60 degrees. All our reef tanks are in the 70s, and that throws off the reading which is why hydrometers usually read lower then a calibrated refractometer. You can see this by putting water in the hydrometer and getting the reading, and then letting is sit and cool off to a lower temp, and you will notice the reading has changed. But its good to have both as a backup... I know that my hydrometer reads .002 lower then my refractometer so I have a sort of check system in case I think something is wrong.
Since pecific gravity actually fluctuates with temperature, most people use the ATC refractometers which actually reads salinity in ppm (parts per million) and then shows what the corresponding specific gravity reading on the opposite side of the meter.
The problem with hydrometers is that they are temperature sensitive (they work on the principal of water density and water density changes with temperature) and they are usually made to be accurate at 60 degrees. All our reef tanks are in the 70s, and that throws off the reading which is why hydrometers usually read lower then a calibrated refractometer. You can see this by putting water in the hydrometer and getting the reading, and then letting is sit and cool off to a lower temp, and you will notice the reading has changed. But its good to have both as a backup... I know that my hydrometer reads .002 lower then my refractometer so I have a sort of check system in case I think something is wrong.
Since pecific gravity actually fluctuates with temperature, most people use the ATC refractometers which actually reads salinity in ppm (parts per million) and then shows what the corresponding specific gravity reading on the opposite side of the meter.
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- Location
- Rego Park, Queens
I only use a refractometer...I find that swingarm hydrometers can vary widely, even with the same sample at the same temperature...and the swingarm tends to get stuck. Some brands are worse than others..the coralife one never worked at all.
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