under dilute formula milk by mistake

My baby (13 days old) had been taking breastmilk and formula milk. My husband had accidentally been giving baby under diluted formula milk for about a week. He would put the powder in the bottle before pouring in water. I only found out recently and had changed the way formula milk was mixed. While baby's poo and pee appeared to be normal (poo about 2 times per day, urinate about 10 times a day), I am worried whether there is any impact on baby's health??