cacti turning yellow

Question

I have a few types of cacti, two of which are turning from green to pale green. they are in clay pots.

Answer 1

This could actually be too much sunlight.
Over watering can also cause a yellowing of your Cactus, and can lead to root rot or fungus.

https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/cacti-succulents-inside-your-home.htm