I emailed them about this sand. They said the location that they were getting the sand from no longer can produce a quality black product. So until they locate a new location to source the sand from it's unavailable.
I think this was near two years ago now. Luckily I have one of my 125s full of it.
Hunting for an alternative I tried the Imagitarium black sand from Petco. I found it to be more of black crushed rock not so much natural sand, also it's a lot darker in tank compared to Tahitian moon. I warn against it's use with heavy digging bottom feeders like Cory cats. It's pretty sharp and caused 9/10 Cory's to die, they literally ground thier faces off doing their natural foraging.