I used to use VHO but changed to T5 a few years back. There are several benefits to using T5, more lights per space, less electricity, individual reflectors, etc. My tank was doing good with just a 250w 12 Reeflux bulb but when I added the 2-420nm and 2-460nm T5 bulbs, I noticed an immediate coral growth. VHOs are for supplimentation but you can light the whole tank with T5s.