MBL- I have two 20w 6500k curlies over my 5.5. They work great and are cheap to do. but I think you might be better off with more traditional offerings. Mine don't seem to be showing all that great coral growth.
With the curlies I think you are losing some light because you can't fit them with a good reflector and the curls on top are blocked a bit by the ones on the bottom. You can just run a workhorse 7 ballast for $30 and have 220 watts of pc or vho. I would go for vho because the URi's have an internal reflector and you could pack a bunch in the hood. You might have to change vho's out a bit sooner than pcs but with a shallow tank they should give plenty of light.
You can get a 42watt 65k bulb here
http://1000bulbs.com/category.php?category=670
two of them would probably light up a ten real nice but then you are still going to have to run actincs on a sparate ballast. They also sell workhorses for cheap. It is not a big deal to wire them if you are non diy.
I would determine how much light you want over the tank and then the length and go from there. Make a list with Vho's PC's and screw ins and compare the costs.
I imagine three vho internal reflector tubes and one ballast will give you the most bang for the buck if you are not going halide.
Tom
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