lighting and nitrates

[cjw]

I have a 210 gallon tank that I am having problems lighting I would like to house clams and stony corals along with soft. I currently have T5's and am interested in metal halide lighting.
I'm confused on what I need and don't want to deal with a chiller.

Also I am having some nitrate problems. I'm not sure how to take care of. My nitrates are currently at 80ppm

Thanks
Connie