carib sea aragonite, is a bit more expensive(actually alot) then south down, but it can be found at many online retailers, just be sure to specify oolitic, or grain size, tehy also sell a aragonite cc(which you do not want), or you could go and get quickrete(you know the cement company) which is quartz based and it will work, i know of many others who have used it with no problems,
and if you are nto getting any ls now, why bother, the lr will seed you rbed too, the ls more than likely be only wet sand and bacteria(if you are adding sand after teh cycle, i would use ls, but not for the cycle if you are using lr) and the rock will provide much more life than just bacteria to the sand, by the time the cycle is complete, and the bacteria will colonize by itself
HTH adn good luck
btw, squidworth, check your mail