Perhaps a small incremental change in water could be considered until the water is is changed over to an amount fitting with necessary water parameters for the GF. I would be concerned a drastic change to their water situation could have undesired effects.
GF like harder water as a norm, though yours are used to much different water parameters than what would be naturally desirable.
GF like harder water as a norm, though yours are used to much different water parameters than what would be naturally desirable.