ksc does bring up a good point. If you don't need to overdrive your bulbs (which you will with the Icecap ballasts), then you shouldn't. When I used T5s, I was lighting a 90g (24" high) with only 4 T5s, so I wanted to overdrive to get as much light as possible.
Depending on what you're keeping in your tank, if you don't need lots of light, I agree with ksc - just get a normal ballast. Reefgeek has kits with normal T5HO ballasts (Universal Accustart), but don't think they carry the ATI reflectors. The Icecap SLR reflectors are still darn good, though.