Advice please answer

My daughter was born at 35 weeks and she's been on Similac Neosure ready to feed for premature babies.

No problem with the formula at all. It's helping her gain weight really well. The pediatrician recommended the liquid because it's more "sanitary". But she said if it's hard to find in stores powered is fine too. She's 2 months old now. The formula is almost impossible to find in stores near me. If I can find it, I drive 20+ minutes to a Walgreens or cvs and just find one bottle.

I wanna switch her to powered formula now but I'm nervous since it's less "sanitary"

I know the pediatrician said it's okay but I just want advice from other moms too. What type of water should I mix it with?