Folks, if you've recently upgraded or renewed your annual club membership but it's still not active, please reach out to the BOD or a moderator. The PayPal system has a slight bug which it doesn't allow it to activate the account on it's own.
HPS put out an extremely yellow light, even more so than 6500K MH bulbs.
Lighting under HPS tends to wash out all color, sometimes to the point of making the "subject", in this case the tank, look almost like a black and white photo. You may have noticed this under some types street lighting, that are HPS. Thus usually isn't your goal with a reef system.
Considering that most reef systems use lighting in the general range of 10000K to 20000K, which is white to blue white to blue, HPS is generally not recommended for use on a reef.
Like anything else, I suspect it's possible to "make it work", but you can do a lot better with MH, LED, T5, VHO or PC lighting.