Background Reading: 6-I: Insect invasion 

Tips:

-If you notice wasps in the general area of the hot tub, watch to see if you see any of them land on the tub and enter through some crack or hole. There could be a huge nest hidden inside.
-Look for dust and tiny shavings along the bottom behind the skit panels, droppings which may come from ants, termites or boring beetles above. 
-Look for foam that looks like intricate Swiss cheese from tunneling beasties
-If you see an insect or two, pause to see if you can find where they’re coming from, in case there are lots more.