What's the ECL for a Maralith?

[Leopold]

Anyone have any idea? I am shooting for around 20 as the CR is 17 and lots of abilities. Anyone fathom a good guess?

 

[Hand of Vecna]

According to Soldarin's ECL Calculator & Guide, a Marilith's ECL is +22.

 

[Leopold]

thanks' that's just what i neededd.