Water Salinity Question (hydrometer)

[mlovelace]

Hello forum, I did a water change this past Sunday and followed my directions very closely for adding Salt. I tested the water and noticed it jumped up from 1.023 to 1.030. Could I have a faulty hydrometer or do you think I just screwed up? I have a 75g tank, trying to figure out how much water I should take out to get the level to drop down to 1.020-1.023? Including the sump, I am probably holding about 60-65g of true water.

Should I go ahead and purchase a refractometer?

Thank you, Mike

Ps....I have a deep six hydrometer (can you calibrate them?)

[leebca]

It's my opinion that every hobbyist with a 29 gallon or larger tank should have and use a refractometer made for salt water.

Hydrometers are adversely affected by several conditions I won't go into here which can still be fine for gimmick (nano) tank or such, but not so good for a serious hobbyist. They are not calibrated. The refractometers are not that expensive.

As to this particular scenario, more likely the wrong amount of salt or water was involved in the addition.