Measuring heat and humidity, Cleaning solutions

[Barking Deer]

From what I have read, heat guns are best for measuring, but what brand is most recommended? Is there such thing as a humidity gun? If so, what brand is best? If not, what is best to use to measure humidity?

The tank I will be using used to be used for turtles and it has those water stains on it, and I'd like to know what cleaning solutions are best to clean the glass.

Thank you!