We use a gnarly power sun bulb. But most places im members on say add 5% uvb power for screen tops.
Any way you can strap the light to the bottom of the screen? Or in the tank? Thatd fix ya up i think.
Btw be careful with the t5. Its in general light intensity may cause eye issues. Tell #1 will be them looking like they have bags(dark rings) under their eyes. Personal experience there(insert long sigh)