I was recommended miner-all here for a young sulcata eating soil. I am unable to find it anywhere around where I live. I always prefer actual stores when buying things. I have found things like Exo terra multivitamin. Is this comparable?
What foods are you feeding your tort?
If you have the correct foods then you shouldn't need any additive other than maybe some calcium/cuttlebone.
A proprietary tort food like Mazuri or ZooMed Grassland used as a supplement will also provide a vitamin/mineral boost.