Chameleon cage and substrate

Hi! I was wondering what size cage i should use for my new 5 month old veiled chameleon the one i have now is only about a foot by a foot in a half and isn't working so well. Also, what type of substrate should i use i have coconut fibers now but i heard they are not good. Thanks for the help!

Substrate and Cage

At least 18*18*36 cage although average is 24*24*48. As for substrate you can use this: http://www.petco.com/product/104018/Zilla-Green-Reptile-Terrarium-Liner.aspx?CoreCat=OnSiteSearch, Nothing or paper towels/newspaper. If I'm correct your Cham has MBD so, if you get a bigger cage put it on its side so if he falls it wont be from too high up.

Okay thank you so much!

Your welcome and best of luck!