The best solution is you put the hole substrate out of the terra and clean it..
After that you take normal substrate like earth.. You put some rocks and plants in the terra. What size have your terra?
Top soil from where? A gardening store? Because top soil can have perlite and other fertilizers in it which is fatal. I'm not familiar with the limestone, but if it is like a gravel then I would cut back on it. Rocks in the stomach cpuld turn to a form of cement. I use dry clean dirt dug up from 2 feet under ground mixed with coco coir and eco earth.
3 feet by.....? Russians need lots of room to run and explore. My (5) live in a 70 square foot area, it sounds big but its the minimum for as many as I have. Also, is your habitat indoors? Does she get exposed to sunlight at all?
I wouldn't use a substrate that has things in it to encourage a tortoise to eat it. If it were me and my tortoises I would not use the substrate with sandstone grit in it. Eating dirt of any kind and not being well-hydrated will cause impaction.