Heat lamp stress?

[MarkS]

My ambient temp is a steady 89-90 during the day and my uth is at 90. My humidity is a steady 56.

In my opinion ambient temps of 89-90 are way too high. How are you measuring your temperatures? I personally shoot for an ambient temp in the mid-70's to low 80's with a hot spot of about 86-88 degrees. If you are concerned about the light, you can alway use a Ceramic Heat Emitter (CHE for short) instead of a light bulb. With a 75 watt light bulb hanging over a 20 gallon aquarium I can't imagine that you are having any kind of luck maintaining a decent humidity level, what are you using to measure your humidity? Cheap hygrometers are notoriously inaccurate.