Thanks for your query.Based on factyou have posted it appears that you are passing Uric Acid stones through urine.This is due to higher concentration of Uric Acid in blood and urine.Low urine output and acidic urine is also one of the reasons to form Uric Acid stone.As the uric acid stones are formed due-to high level of uric acid you have to modify your diet as follow
Please avoid animal proteins
in your diet
Avoid alcohol and caffeine and take minimal protein
Drink at least 5 litres of water in 24 hours so as to keep your Urine alkaline.
Consult physician to get prescription of drugs to lower down the uric acid levels in your blood.
All these measures will help to avoid formation of Uric acid stones.