From reefbuilders, things u can do to improve coloration of different colored sps.
http://reefbuilders.com/2008/09/03/guide-of-sps-coral-coloration-make-them-more-vivid-bright/
Potassium only affect pink/red and some purples in sps.
Agreed with bro reef garden that your tank is really inspirational. Sand bed still got space, can load in more popular lps like Scolymia, Acanthophyllia aka prata. Lol
Ya, maybe not recommend for beginners. Not sure wat the tool is call though, can use a table electric saw too. Use protective goggle and just push the lps through the middle or which part u intend to frag.
It can be fragged but u need a specialized cutter like the one in GO. Sorry, dunno what's that tool is called.
http://www.reefcentral.com/forums/showthread.php?t=2222107
Try feeding more amounts of food per feeding session. When the faster swimming fishes have their full, hopefully the leftover will be taken by your YT.
Depends, most zoas need moderate to strong lighting so dun think its good to place them under shade. U see them stretching their necks to get more light.