I have a fiberglass tub with tile on the walls surrounding it. At the joint where the top of the tub and the bottom of the tile meet it has been sealed with what I can only describe as a putty. It is definitely not grout nor does it seem to be silicon caulk. The sealant was cracked on one end of the tub, so I have cleaned it out and would like to reseal. The seems on the other two sides of the tub are intact and holding up well, I would like the third side to match but am unsure of what they used originally. It is a dark brown color and matches the color of the grout. I used a putty knife to clean it out and while the surface was fairly hard it is kind of soft and crumbly when you dig into it. Any ideas what it is? If nothing else, does anyone know who makes a good bathroom caulk in a dark brown color? I hope my description makes sense. Thanks for your help!

 

I would assume they used a color caulk that was most likely purchased at the tile store. Paint and big box stores will have a small selection of colored caulk. A tile store should have caulks that match most of their grouts.

Be sure the crack is clean and dry before you apply the caulk. Alcohol is good for cleaning and a hair dryer can help with the drying.