Hi flower_addict88,

I found this info from the link below.
"about color
- If bulbs are planted in deep shade, the green color
of the caladiums will tend to dominate
-If planted in highly acidic soil, the darker colors will
dominate
- Miracle Gro can cause color variations - use
carefully
- Several varieties change color as they mature -
please be patient "

The link below has a lot of other good info too, including winter storage.

Sue

Here is a link that might be useful: Planting Information

I would try brighter light first, then a fertilizer higher in potash. Sometimes more magnesium (epsom salts) helps, too! Good luck! : )