Most clams need MH
but there are some low light clams that can be kept.
I have VHO
on my 125 reef 4x110 2 icecap ballasts 2 actinic, 2 super white and I have hammers, frog spawn, alveopora, bubble, 2 kinds of leathers, torch, kenyas, zoos, shrooms
, galexia, button polyps, yellow polyps, fox, xenia..... I am sure I left out something. I like the VHO
system, with the MH
my tank would be running hotter and I would need a chiller so more $$$.
I have seen tanks with PC
lights and they are nice. The T5 are the new lights that a few guys in my reef club are using and they like them a lot.
you need to change the bulbs out every 6-8 months, PC
12-16 months not sure on the MH
and T5 lights.
Keeping tank cool is something to think about and cost of electricity with MH
lights may be more. Do some shopping around and see what fits you wallet/pocket book