I have a 5.0 UVB light. I live in Central Texas, very warm and humid. I have a 5mo Redfoot that I take outside in semi- shade for about 30 minutes a day. He loves eating our St. Augustine grass (no pesticides or herbicides added). Here's my question: How long do I leave his UVB light on during the day? Enclosure maintained around 85 to 90 with 80% humidity.