#gravel

So I’m looking to change my gravel to sand. Is pewter sand ok for corys , I’ve never had sand in an aquarium only gravel so not familiar , I did read that Caribsea sand is good however don’t have £35 just to spend on sand , any help or alternatives ?

I currently have gravel in my aquarium but really enjoy having catfish in my tank especially Corydoras , some people have mentioned I should change my gravel to sand as it’s better for their whiskers and bellies on the bottom, but I have substrate mixed in with the gravel , is there any easy way...