Can someone explain to me how you prepare/store powdered formula for multiple babies? I've been microwaving the water and then adding the powder, but then I can't stick it back in the fridge to store it? And it seems like when I add the powder to the cold water (coming from our fridge filter) it clumps and doesn't mix as well as when its warm water. Forgive me if this is a no-brainer--I've never in my life used formula so this is all new to me! I need some tips to make it easier!

Re: help me with formula ?
We use tap (given the ok by our ped) or bottled water. We pour the water, add the scoops of formula, shake to get all the clumps out and stick the bottles in a bowl of hot water (or let the hot water run over them) for a few minutes to get them warm. Sometimes, if they're screaming, we just use room temp water. They don't mind.
We use up & up now that they're older and I find that it mixes better than Enfamil or Similac for some weird reason.
I know some people mix a big pitcher of formula and pour and heat as needed. Others make all the bottles for the day and pull them out and heat them as needed.
We do exactly this as well.
I have a Brita water pitcher I got off Amazon. The water stays room temp and I just mix the bottles with the powder as needed. If for some reason it feels cold I heat the water for about 5 or 6 seconds in the microwave and then mix.
I think the clumping also has something to do with humidity. I have days I feel like it clumps up more and I'm using the same temperature of water.
We do this exactly. After we put the girls down for the night, we make all of the next days bottles. It makes things so much easier. I definitely reccommend the formula pitcher!
Make it a Double