You can find reptile light domes at just about any pet supply store that sells reptile supplies. You want to make sure that you get one with a ceramic socket as there is no risk for melting then. Your lights may also be breaking for other reasons. i have had bulbs explode on my turtles before because of water splashing up and hitting the bulb. the cold water hitting the hot glass will make the bulb burst instantly. If this is the case i know that zoo med makes a turtle tuff halogen lamp that resists water splashing against it, here is a link for that particular bulb:
http://www.thatpetplace.com/pet/prod/239527/product.web
And as far as your water dragon, if you spray the tank and any water gets on the bulb it will break the same way. Touching bulbs also makes them wear out faster but i have never heard of them breaking from this. Try not to touch your bulbs excessively, the oils from your hands can get on the glass, when the bulb heats up, it will get hotter in the spots that you touched which can cause the bulb to burn out.
good luck, if you even see this reply, these forums are getting really slow!
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www.myspace.com/ThirdDimensionReptiles
My Kids:
The Scaled:
0.1 Savannah Monitor
2.5 Leopard Geckos
0.1 Green Iguana
1.4 Tokay Geckos
1.1 Bearded Dragons
0.1 Golden Gecko
1.0 Burmese Python
1.0 Het. Albino Ball Python
1.0 Lavender Albino Cali King
1.0 Black RatSnake
The Furred:
0.1 Ferret
1.0 Chinchilla
0.1 Hedgehog
1.0 Sugar Glider
0.1 Rat
1.0 Cat
The Feathered:
1.0 Citron Cockatoo
0.1 Goffins Cockatoo
1.0 Cockatiel