[Fluxburn]

I have this nasty calcium deposit build up near the drain of my bathtub at this apartment. The only thing that removes the build up is a lot of work using pumice stones to slowly remove the buildup.

Is there any chemical of any kind that will actually help chemically break down calcium? So in chemical terms I want to turn the calcium into aqueous form.

[jdurg]

Use an acidic cleaning product.  The buildup is most likely calcium carbonate (chalk) or calcium sulfate.  If you use an acidic cleaning product, you'll make the calcium salt soluble in water so it will wash away.  Something like CLR or muriatic acid will do a good job at removing the buildup.

[constant thinker]

I used bleahc on my bath tub and scrubed. WARNING make sure you have good ventilation and rubber gloves. I got a chemical burn on my hand from the chlorine in the bleach and my eyes stung, and I was coughing alot. I learnt my lesson about halogen gases. Also I heard that pouring very salty water  in a tub and letting it sit for a while will work.