Teen series from the '90s about a foster home

I think there were three books in the series, and I vaguely remember them having titles like 'Fire' and 'Ice'...

Other things I remember:

\- The protagonist was a teenage girl who had to move towns to live with this foster family who had a huge house. I think she lived on an island and they lived on the mainland, or maybe the other way around?

\- The foster parents seemed nice but possibly a bit strict at first. As time went on, they sought to 'erase' the personalities of the kids in their care.

\- Once the kids had been brainwashed/'erased', their room was decorated in a theme that represented their old personality - so a previously happy kid might end up with a sunny yellow room, etc.

\- The foster dad had gray/silver eyes.

\- One minor character was named Valerie - she was a former foster kid who ended up in a psych ward.

I might have mis-remembered some of these details! It was a series I remember enjoying as a 14 year old - around 1993.