Lighting help
 

I am looking at upgrading my lights from just compact fluorescent and i am trying to decide between these two fixtures
Coralife lunar aqualight T5 HO 4x39W plus moonlight LED or
Tek-light T5 4x39W (or possibally the 6x39W)
I have mostly LPS and soft corals but i am looking at starting to get into some easier to keep SPS.
Does anybody have any of these lights or what light would be best to get
Thanks

How tall is the tank

I have the 6 bulb tek. It's sitting 5" above the surface & it's about 19" to the sandbed. It works great for lots of sps & a few zoas & 2lps frog spawn which is mostly under an overhang & a candy cane that is in the sandbed. I wonder if it was higher if my purples would get darker? Any thought's Laurier?

the tank is 18"

a 4 bulb tek would be perfect for what you plan on keeping. I know the coralife sounds amazing for what your getting (legs/moonlights/fans) but to be honest with you they really aren't a nice fixture. I have one right now and even after changing out a few bulbs it seemed to be a bit dim for a t5 fixture. I like my tek but i wish it was an ati lol
Mine were actually maybe 10" away from the light max when I had my deep purples. I found that the less you change stuff in the tank (dosing or what ever) and you stick with a solid type of salt they will eventually come out. Purples to me seem to be more concentrated on water quality. when mine came out the most I just laid back and did nothing... literally