Spit up

My daughter is 5 months old and we had to supplement formula for her weight gain and eventually she weened off of me so shes formula fed now. She does not have any allergies or reflux but she spits up so much and we had to combine enfamil AR and gentlease to keep it at bay but she SOAKS a receiving blanket and 2 burp rags every feeding. Her pediatrician says sometimes babys just spit up. She wont keep anything similac down but weve tried a variety of formulas and none seem to eliminate the spit up