My unfinished basement has some sort of white paint/coating on the cement block walls, but it does not look like it is one of those masonry waterproofers. I want to put a masonry waterproofer on the walls to make the basement look nicer/brighter and avoid any chance of future water seeping through. Do I need to etch the current coating? Or will a simple cleaning with TSP substitute do the job? Thanks in advance!