Ok so the T 8 needs to be unobstructed NO screen and NO cover - for now I recommend you change out the bulb to a Repitsun 10.0 T 8 better bulb - fixture is fine --when you get the UVB situated please take a piece of decor and have it directly under it 6-8 inches this bulb will need to be changed out in 6 months I recommend 5 -- you will need to upgrade the UVB to atleast a 24" fixture when the tank is upgraded ------ I would be looking for a new tank of 75-120 gallon -- you can look on FB Marketplace or Craigslist -- look for one w/ front doors and if you find one make sure you sanitize it real good w/ F10 found on Walmarts website its spendy but real good or some Rescue or Zoo Meds Wipe Out - if you need help getting the UVB inside I can post some things to hang inside for you or take the screen partially off where it has no obstruction - like setting it width wise across the tank and have the screen 3/4 on w/ the screen butted up to the UVB and basking bulb beside it