Hi Vitae
[welcome]
That's fine for a 20 gallon. Power Compacts are often used on a small reef as you don't have a lot of room to work. Yeah, you can drop an MH pendant but you end up with more light fixtures than tank. You can also use T-5 but as you already have PC I'd run with it. With 130 watts you can have just about any coral you choose and even some high light organisms just by placing them slightly higher on the rockwork.
Darn, I may need to rename this the Welcome Banner thread.