Hello. This is the info I have on lemon juice to dissolve small kidney stones. Drinking four ounces of reconstituted lemon juice in two liters of water per day. Try that. 1 Tablespoon is an ounce, so 4 Tablespoons of lemon juice in water over the course of the day. I don't know what dose of Vitamin C you take but high doses should be avoided as they are associated with the most common type of kidney stone formation. The amount in your multi vitamin probably is not a high dose. Hope this helps.