I dont think you should waste your time doing that ,in a few days your pump with have some algea and full of coraline in a month or so with good water parameters ,JMO
I used Krylon Fusion to paint some PVC in the tank and it's been perfectly fine IMO. It's pretty covered in Coraline like others mentioned but it does take some time for the object to be completely covered in coraline where you wont see any of the white... or whatever you're trying to hide.