Help! Salinity Reading Issues

I'm having an issue with measuring my salinity. I was using an Instant Ocean Hydrometer, but recently purchased a Refractometer from National Industrial Supply on Ebay.

I did a water change last night on my 37 gallon and when I measured the salinity with they hydrometer last night it was about 1.024-1.025. This morning when I measured it with they hydrometer it was reading 1.028!! I measured with the refractometer and it says about 1.024.

Before adding clowns to my 90 yesterday I tested the salinity with my hydrometer and it was about 1.024. My hydrometer is giving me the same reading this morning, but the refractometer is giving me about 1.020-1.021.

What is going on?! Now I'm worried the salinity is too high in the 37, even though the refractomerer says it's okay, and I'm worried the salinity is too low in the 90, though the hydrometer says it's okay. I don't get why the numbers are so different, and why the hydrometer seems to be reading one tank correctly and not the other....

Anyway, any insight would be greatly appreciated!! I don't want to mess with the salinity and hurt my fish.

 

Those Hydrometers dont read to correct if not cleaned properlly all the time, Could just need a better cleaning, I swore I saw someone say they use vinegar and water to clean it... Im not 100% sure. though on that.

 

Have you tried soaking your hydrometer in vinegar? Sometimes if you don't rinse the hydrometer out properly your readings will be off. Rinse it out and soak it in vinegar then try again.

 

Yes, I have read that. I have no vinegar though....

and I'm having a hard time trusting the refractometer!

 

If you don't have vinegar soak it in water for a little bit then rinse it out with water from the faucet. The pressure will help loosen any salt or calcium. If the refractometer is correct each time trust the refractometer.

 

I'll try that. I need to get some vinegar.

But what I don't get is why it's reading the same on one tank, but much higher on the other....

 

Is it every time it reads higher on that tank? The reading of 1.028 may be an outlier from some sort of user error or error in the swing of the arm.

 

Hah, Get some vinegar and see if it is a trust issue or not

 

Trust the refractometer over the cheap hydrometer. Also don't forget to calibrate the refractometer with R/O!

 

Make sure your refractometer is properly calibrated before you take readings. You can use RO/DI water to zero it out (it's not the most accurate but it works).

I'm sure somebody else can help me out with the proper calibration solution?