What to Do...?

I bought a small peace lily many years ago. It had lush green leaves. It grew and eventually bloomed - some years producing several flowers.

A few years later, it stopped blooming at all. Eventually, I decided to divide the plant - maybe it had outgrown its pot. Repotting it, I discovered that the pot was totally root-bound. In fact, I had to cut the roots with a garden saw to divide the plant. 

I put the roots into three pots, added fresh potting soil, placed them in a north-facing window for indirect sunlight - and continued to water them, hoping for an abundance of flowers.

Long story short, there was no amazing recovery. Only two of the three ever bloomed. And the leaves of all three plants were pale and yellowish, rather than lush green.

What could the problem be? I looked up "peace lily yellow leaves" in a gardening website... and found no answers - only questions!

Are the yellow leaves on the bottom? If so, the yellowing might be part of the natural process. They may be dying to make way for new growth.

Are they on top? Maybe there is too much sunlight. Or... too much water.

Hmmm... I don't think so.

Do they need fertilizer? I assume that the fresh soil would have adequate nutrients for a few years... i haven't fertilized them.

Maybe I should put them in a new location. Sometimes, for some unknown reason, that makes a difference.