We have had a chronic leaky faucet in our deep soaker tub for a long time (over a year). We have been unable to remove the taps successfully and don't own proper tools (pliers, proper wrenches, etc.) so we have decided to call in a professional to change the fixtures altogether (they are super-cheap builders fixtures & are now corroded). My question is that there is a light-blue ring around the tub now. Does this mean the finish is ruined on this tub? Is there any special way to fix this without refinishing the entire tub?

We can't blame the faucet for the blue ring in the tub. I assume the tub is plastic or fiberglass and not cast iron. Have you tried soft scrub or bleach on the stain? What do you think the blue stain is? Most tub stains are brown or reddish and are caused by iron oxide, (rust) in the water or built up in your water heater. For stains on porcelain I soak some paper towels in full strength bleach and let them set on the stain overnight. Let me know if any of those worked for you. Regards. Tom