How hot is your hot tub? If you do not know you could find out with a hot tub thermometer placed inside of the hot tub itself. You see if your hot tub has a manual then the right or appropriate temperature should be listed. If you measure your water temp and it is not right something could be wrong with your hot tub. So having a thermometer can help you to catch problems early.
When people ask me about building their own wood fired sauna, the one thing most of them are concerned about is the steam quality. Why this is, I'm not quite sure, but for some reason most people think that is the main relaxing characteristic. When in reality it's not just the steam, but also the aroma of the word itself that gives off relaxing benefits. A form of aroma therapy if you will.
My friend uses many thermal signet flow meters in his crazy fluid flow rate tests. He says that he needs these thermal signet flow meters because they are non-intrusive and won't disturb the fluid that he uses for his weird science experiments. I don't pretend to know what the experiments are, but if they require thermal signet flow meters, it must be very important to my friend. The signet flow meters he uses are top quality as well.