How old is your tortoise? For a growing baby russian, I would use just a pinch on top of the food twice a week. For an adult male I would not use any, or maybe just once a week.
This assumes you are feeding a good diet of weeds, leaves, cactus pads and other calcium rich foods. If you are feeding romaine lettuce, you will need more calcium and have lots of other issues to solve too.
He is at an unknown age but he is about 6" long , i usually feed him carrots and romain lettuce , but I'm going to try some of the more expensive, more healthy foods like you suggested , and could you suggest some more good foods for him , thanks!!!
Broadleaf weeds are best. Look for mallow, filaree, dandelion, wild mustard, wild onion, sow thistle, milk thistle, clover (NOT oxalis, which looks similar), plantain (the weed, not the fruit), and lots and lots of others. Try to ID the ones near you. Post pics here or take samples to a local nursery.
Leaves from mulberry trees, hibiscus bushes, rose bushes, and grape vines.
Mazuri tortoise chow and or ZooMed Grassland tortoise chow.
From the store: Endive, escarole, turnip, mustard, and collard greens, cilantro, carrot tops, all the lettuces, chards, radiccio, watercress, etc... Variety is key, but I like to favor the first two most heavily.
This list is just a beginning. There are literally dozens or hundreds of other good items to be fed too. Make sure ALL items are chemical free.
Remember- calcium powder is bitter and looks like powdery mildew- yuck. Use it very sparingly- try to use a good diet instead.
When you DO use calcium powder, some things that generally work are things already mentioned or a couple other tricks-
- lightly mist the greens, add the powder, and toss to mix it around.
- touch a side of a few pieces of moist fruit into the powder (for fruit-eating species)
- mix the powder with some chopped up rabbit hay to get a twofer supplement- calcium AND fiber!
If you incorporate grassland diet to the tortoise's food, you would't have to add so much calcium all the time. A balanced diet doesn't require much supplements.