I cant think of the name, but there is one that has living sand. Comes in 20 and 40 lbs bags. I thought that was the best b/c of the natural elements it contaibns. Caribsea I think(I might be way off and thinking of the beer)?
For 90Gl reef tank, id say >90 lbs LS and what ever color you like. I think Black is cool(might be alittle 90's cheesy, but I dont care about that).
Good Luck
I got mine on ebay and was happy with it. I wanted sand with critters not just bacteria which is what you get from the bagged sand. You have to decide what kind of sand you want and whether you want a deep sand bed or not. Sand like sugar will be the least troublesome as it does not trap stuff like the larger crushed coral does. If not a deep sand bed then keep it to an inch or less. If you have sand sifting fish or wrasses they also prefer the smaller crystal type sands.
small size sand has greater area for bacteria growth too. its hard getting live sand with critters due to die off during shipping. i rather culture my own with good LR n/or seed from an establish live sand.