ok heres what i can share wiff u...
1) for how much salt to buy..
i think for a 6 feet tank a bucket would be good..
as for choices of salt mixes... u can go to this post http://www.sgreefclub.com/forums/index.php...a078d2d2ee3c688
2) for the sump u can click here
theres an adress of a tank maker there...
but be sure that u have yer designs ready...
do a search on the forum... theres alot of ideas of sump design u can copy from our fellow brothers....
3) skimmer wise... i think the others can comment.. not so sure whats good for a 6 footer
4) as for sources of fishes...
theres a few threads on this...
you could tell us where u stay so we could give those that are closest to u...
just my 1 cent worth