I like 5 (purple plus and AB Special) and 7 (purple plus and coral plus).
I would also like to know how many and in what order they are running them? Are they running them every other bulb, one and then the other?
I currently run the ones below, which look more like 5, a little more white due to a 10K bulb in the mix.
6xT5HOs (front to back)
*ATI Coral Plus
*RS Actinic
*ATI Coral Plus
*RS Actinic
*RS 10,000K
*ATI Actinic
You get better growth from sps on 10Ks so might as well run at least one of them.