My hair was dark brown naturally, like 5 years ago. I dyed it red for 4 years. A few months ago I died it blue black temporarily.now I want to dye it blue onyx using MC Max by miss clairol . Should I use a 30 volume cream developer or a 20 volume?

The 30 volume developer will be too strong. Use a 20 volume strength developer with the Blue Onyx hair color .