sand is easier for them to dig into, but likes to collapse if they dig to big a burrow
I usually use a huge tote, then pile moist soil on one side about 2/3rds the way up, then start a hole for them going into the side of the mound twards the bottom. They'll usually gladly use the prestarted hole and save themselves a little work. I think the more soil you use, the less chance there is of collapse when they dig into it.
I would double it if possible. if she digs a hole 4 inches tall, theres only a 3 inch roof, and it will probably fall in on her. Everyone has what they like to use. I just hate seeing them put a ton of work into digging just to have it fall in on them, and regular old fashion dirt seems to hold its shape the best. If you do a mixture, I'd go easy on the sand part. Having enough moisture in there helps it hold to. You dont want it muddy or anything, but it shouldn't be dry either. I shoot for what I think will stay together, like where you can make a dirt snowball with it.
Thanks for the advice guys!! i had bough the compressed eco earth but its made out of coconut fibers, doesnt clump or ball up :-/ im such a beginner at this she hasnt laid yet so tomorrowi will get sand ( regular playing sand ) and mix it in so hopefully it clumps up and ill fill the 30 breeder up atleast half way or ill get a pretty big tub!, my incubator comes in on monday or tuesday, i hope she holds off till then.