[gargoyle]

What other types of sand could i use in my tank if i could not find any southdown or old castle?

 

[MontanaRocknReefer]

There is aragamax sand! Will cost more to get what you want!

Here is a link:
http://www.premiumaquatics.com/thestore/prods/C-ARAGAMAX.html

 

[Rick O]

Check with TDWyatt. He's in Greenville and may have some Southdown.

If that doesn't work out I would try Pure Caribbean Aragonite. They are a sponsor here and a good company to work with.