Our bathroom floor has ceramic tile over Hardi-board and a wood sub-floor. It butts up to a fiberglass shower enclosure with glass and metal shower doors. Over time the tile grout has pulled away from the shower enclosure. Now the shower door seals aren't working and water is seeping over the edge of the enclosure and down into the opening in the grout. I am very concerned about mold under the tile. Short of removing the tile and reinstalling it, what is the best approach? I'm thinking I should spray a lot of bleach/water mix into the crack to try to kill any mold that is getting started, then stop using the shower for several days in order for everything to dry out. After it appears to be dry, I would reseal the shower door and repair the tile grout.

today the plumber noticed minimal amounts of water inside the walls of the bathroom. he thinks it's from possible water seaping through the tiny cracks in the tile. the water and moisture is causing a musty smell and fungus growing inside. actually, we noticed the problem last year when mold was growing underneath the vanity sink, but didn't know why. so the mold remediators dried the walls inside and cleaned up the mold, thinking that would be the end of it. unfortunately it's back (the water) and is causing some bubbling/blisters to appear on the laminate flooring outside the bathroom. what should i do? it's a rental property and i really don't have much money to do an expensive fix. the plumber recommended tearing out the old tiles and putting up new tiles with a moisture backer, etc. he also noticed the tub is not level, and suggested i fix that too. he also recommended a new tub surround/enclosure instead of new tiling. both jobs he claims would cost me over $2000 or so. please help. that's a hefty amount. what are my options? can i just fix the broken tiles or do i need to replace the whole thing? is it better to do the surround/enclosure? what brands/material should i use? should i hire a contractor or professional tiler/installer or just the plumber? p.s. i know ABSOLUTELY NOTHING about home repair. don't want to be gipped but don't wanna be sued by tenants either.