Caution for anyone using a refractometer

[Doo]

ok - so how do I fix that?

My temp is at 79.0

[fencer]

I think you are okay. Most instruments are have a tolerance range. So you can be off on Temperature. Just as long as you do not mix salt at below 15 and I would say not much above 20C. Just be consistent when you make a batch of saltwater up.