[Cob] Salty cob?

[James Thomson]

I am wondering if anyone has experience with any of the following:

1) Mixing cob with salty water (sea or brackish)
2) Mixing cob with coral sand
3) Mixing cob with beach sand

I know you're not supposed to mix w/ beach sand because it's round and 
of uniform size, but I'm wondering if anyone has actually ever tried 
it.  I'd like to hear about your experiences if you have!

Thanks,
James