I think We have replied a similiar topic here before.
One solution I recommended, switch to the liquid formular.
They are two types: ready to use, and concentrated.
For baby within a month, I use ready to use. This is the easiest
form to be digested by baby except the breasfeed. It is more expensive,
but very well deserved in my opinion.
The reason for this, I have compared my sister's son who used
baby formular power and my son used concentrated formula
when they were all at the beginning of six months, my sister's son
had constipation quite often, and my son did not at all. When my
mom switch him to concentrated formula, he did get a lot better.
My yoounger one is two years and four months now, I still give
him this formula instead of milk as supplemnet of food.