Doctor said we should add Sodium Citrate to my baby’s formula

Patient: We have a 9 month old baby – he was born 10 weeks early at 28 weeks – so a very little preemie who weighed 1.1kg.He overcame all of this and is now a healthy little boy.He went off his food for a little while and so we went to see a different pediatrician.When there he said we need to be adding Sodium Citrate to his formula – we did this and he really doesn’t enjoy it.I tried it yesterday and it tastes of seawater.I believe the baby hates it as well.I just wanted to get some advice on whether this is safe and sensible?Any information would be greatly received.