Hi guys i need help about my walls. 5 years ago i painted my room with two tones, red and orange. Red using Nippon Vinly Silk and orange using Dulux Pentalite. The walls were painted without using any primer. I painted it over a flat finish white wall. Before i started painting the walls i wipe down the walls with 1 part bleach and 5 parts water. Then two weeks later after painting white spots and patches started to appear on colours. i gave a wipe with bleach and water and it disappeared but return eventually. It really pissed me off. Every 6 months for the pass five year i have to wipe them off. The spots the decreases every time i gave it a wipe though. Now after 5 years i'm planning to paint my walls again to a dark grey tone but this time i don't want to deal with this white spot reappearing. Could anyone tell me if this is mould, mildew, fungus or alkaline. What can i do to prevent this spots reappearing again. this time I'm gonna sand my walls down and apply primer. Need a recommendation of what primer and solution base wall cleaner to use to prevent this spots from reappearing. I could really appreciated the help from you guys before i start painting. Here is a clear photo on how bad these white spots can be. The left side recently wipe off and the right didn't bothered to wipe for years because the wardrobe was in my way.