I have a russian tortoise, is sand ok to line the bottom of her cage with Or should I use something

Sand is OK as long as you can keep it clean- but it is pretty hard to clean the stuff. It is also pretty heavy adn does not offer great footing in most cases.

Most substrates have pros and cons, and a lot of it depends on the exact housing situation you are using.

The site http://www.russiantortoise.org says:

"Once again there are many choices. The ideal is considered to be a 50/50 mix of sand and garden loam. Since garden loam is hard to find here, I substitute Bed-A-Beast or other brand of coconut coir. For me this works well.

"Others have used peat moss..but it tends to be too dusty. Keep in mind that the substrate doesn't need to be bone dry. In the wild they live in very arid conditions. But their burrows have up to 70% humidity!

"Other poor choices are: newspaper (easy to clean); rabbit pellets (tend to dehydrate the tort and are about the worst of the substrates). Also can get moldy fast if wet.); Care Fresh bedding (a recycled newspaper product in a pellet form) Alfalfa hay is too high in protein (torts love to nibble on it)."

I like using the sand/loam mix as well, personally- and I use bagged loam from the garden center. I scoop when I need to and about every few months, I just toss the entire batch into the garden and mix up some new stuff.

In my big pen, I use stone flooring tiles for the basking areas, a washable indoor/outdoor carpeting for some spaces (with several spares so I can have one in the wash, 1 ready to go, and 1 in the pen), and recessed pans of sand/loam for about half of the place. Each pan has several drain holes, so I often dampen the mix to help it pack a little, and offer another micro-climate in the tank.