Normal
Where are you getting your info from? They don't need a light. Also aquarium gravel is a bad idea to use as substrate. Also if I am understanding your post correctly, you use salt or brackish water in the enclosure? Its a spider Not a fish. Sorry if I'm coming across as overly-critical, but you're giving out deliberate disinformation regarding the care of an animal on an internet forum, where other noobs can read this information and make the same mistakes. You said this is only your 2nd tarantula, correct? Before you respond with a defensive post, I am not claiming to be an expert by any means. There are people here who have been keeping tarantulas far longer than I. However considering I have been keeping them for 12 years, I'd say I have enough experience to where I know for the most part what I'm doing. I have never had to do any of the stuff you included in your post for any Avic.