What about the water's pH level when using heat on unstable dyes? I've seen some colors bleed more in hard water compared to soft water. For instance, red dyes in cotton shirts can turn pink if the water is too alkaline. Adding a bit of vinegar to lower the pH might lock the dye in better. It's something to test alongside heat settings. Could that be why some fabrics still run even with high heat?

thomasw48, pebble trays only add a bit of humidity. A small humidifier nearby does a much better job.

Lentils saved my budget too, it's a real game changer.