T8's are not strong enough to go thru the screen the screen blocks approx 30% of the UVB rays-- even T 5's which are stronger bulbs depending on screen haft to go inside the tank - screens act as filters T 8's need to.be unfilteredHow is the screen preventing him from getting uvb? There’s no plastic cover. But I am really having a hard time understanding how a metal, mesh screen is blocking the uvb from entering the enclorsure?