Ideal for RVs and boating, Walex Elemonate Grey Water Deodorizer and Tank Cleaner keeps your sink and drain lines free-flowing and odor-free. Its triple-action formula deodorizes your grey tank, freshens sink and drain lines, and dissolves grease and organic sludge. Easy to use - just drop a tab in your kitchen/bathroom sink or shower drain and run the water for a few seconds until it dissolves. 5 tabs per package. Fresh Lemon Scent.