A mercury vapor that's working properly should not blink. If it gets turned off for some reason, they usually have a built in system that will not let them turn back on for about 15 minutes to allow a cooldown.
If you don't have a UVB meter, MV bulbs can be tricky to use. Many brands are unreliable (blow out early and often) and many more produce lousy UVB. Your best bet for MVBs is to get an externally ballasted Mega Ray from reptileuv.com. They are very reliable and put out good UVB - each is individually tested before being sent to you. If you want fluorescents, the Reptisun 5.0 is the tried and true reliable bulb. I also hear the Arcadia bulbs are good, but I haven't used one of those.
For temperatures and wattage, Lyn is right on. You need a good thermometer and some time to experiment. I have several lights on each cage and adjust the wattage in them as the seasons change. If you use fluorescents or a Mega Ray for your UVB, you will likely need some supplementary heat anyway. Other MV bulbs put out more heat than a Mega Ray, but depending on your setup, you may need more heat with those, too.
Size of cage: the one you specify will be ok for a juvie, but isn't big enough for an adult. You'll eventually need something at least a little longer, if not wider, too.
Sand is fine as long as you get playsand (natural rounded sand, not crushed gravel). They do generally like to dig and will take advantage of anything you give them to kick around.
The most important thing nutritionally is to feed them a wide variety of good foods (a fresh plate once a day is fine). To add to that, you can add in a calcium supplement maybe twice a week and a multivitamin supplement maybe once a week. Keep in mind it's a VERY light dusting - overdoing vitamins is as bad or worse than underdoing them. Also be careful what you're using. If you are providing very good UVB (such as a Mega Ray or natural sun), you don't want to provide any supplements with D3 (Cholecalciferol) as excess D3 is toxic and the UVB allows them to make all that they need by themselves.
I hope that helps. If you have more questions, feel free to ask. Congrats on your new friend! The care sheet at Deer Fern Farms is very good - it will help you out a lot!
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Torey
Eugene, Oregon, USA
1.1 Uromastyx geyri (Joe and Arthur)
3.0 Uromastyx dispar maliensis (Tank, Turtle, and Spike)
1.0 Uromastyx ornata (Scuttlebutt)
2.1 Anolis carolinensis (Bowser, Sprocket, and Leeloo)
0.1 African dwarf frog (Sheila)
1.0 Betta splendens (Mr. Miagi)
1.1 Felis domesticus (Roscolux and Jenny)
