Questions - Need some input

My uncle got out of the hobby sometime around 2004 and sold most of his stuff, this week my parents went to visit and he passed along some of his last reef equipment.

5-stage spectra pure filter, with a pure check monitor, auto shut off, extra DI and chloramine filters
My first concern is what to do with it; I already have 6 stages on my current system hmmmm…11 stage double membrane? This is very tempting. All the filters and membrane need to be replaced which isn’t a big deal ...

that us supposed to be a triccolor front and center there, it is the coral inspiring this question, as you can see there is only growth in one branch, i remember reading a post on a forum saying if i were to clip the "dormant" branches it could encourage new growth. im just wondering if someone can let me know if this is true

today i picked up 2 great frags, a browned out millie that is already turning metalic blue, and a turquoise,purple and orange acan frag....my sand bed is at capacity with frags so its now time to pick a new fish

i just had my very healthy purple firefish die due to unknow reason and my rainford goby and other firefish are getting lonley soo its time to get them a friend im just starting to look so im open to suggestions keeping in mind thast its cool, reef safe, will fit in my 45cube, ...

okay so im going to make this short because i have to run to work sooo

i have the chance to get 2 Helfrichi Gobys for 80bucks, here they are normally 120 each, however in my tank (45cube) i already have a pair of purple firefish, im just thinking similar spicies+bodyshape+late addition= aggresion and dead fish, does anyone know if this will work? they are fairly pieceful fish last i checked.

So here is the problem im having, someone or something in my tank appears to be eating my Acans :/
About 3 months ago i lost a ~7head frag, I thought I was safe till 2 weeks ago when I noticed one of the heads on another frag slowly vanishing and tell tale signs on another.....help
in my tank that i know of i have...2purple firefish, a rainford goby, 1 big turbo, 1 emerald crab and lots of these pesky white star fish that like eating GSP...i think ( thats my next post)
below is ...