Unremovable black mold in the tub

No matter what cleaner or scrubber I use, nothing can make a dent in this. Any ideas?

 

Remove the caulk, and replace it with a tub and tile caulking that is mildew resistant.

 

I agree! caulking is only slightly cleanable and is prone to mildew/mold. You need a caulk that has mildewcide mixed in it.

 

Go to a place which sells chlorine that you dump in a pool. Pour it in a spray bottle then spray on the mold. You'll see it lighten up and eventually you can rinse off. I did this when I lived in Florida, the mold capital of the world, and it worked for me. However, you need to run your ventilation fan and/or have the windows open or else you'll harm your eyes and have a hard time breathing. Wear a mask and safety goggles.

Or if you don't want to resort to the strong stuff, use the kind of mold killer you spray on the side of the house to remove mold from aluminum siding.

EDIT: Please see moderator's precautions above and if you are not familiar with handling chlorine, then I do not recommend you using it to remove the mold. Try consumer grade cleaners instead, but you still should take precautions with at least gloves, mask, and protective eyewear.

 

Regarding the use of pool chemicals, here is some added safety information.

https://www.epa.gov/sites/production...ts/spalert.pdf

I certainly would NOT recommend using a dangerous chemical inside if you don't know what you are doing. Pool chemicals are meant to treat thousands of gallons of water... they are not be mixed with a small quantity of water in a spray bottle.

I would be remiss in my duties as a moderator if I did not add the above to the cautions that were already mentioned about fresh air, a mask and goggles... not to mention chemical gloves and protective clothing.

 

I agree with the moderator's (XSleeper) precautions. If you do not know how to handle chlorine or never handled it before, then I wouldn't recommend you try it. One bad move or ingestion you can harm your eyes or internal organs. Like I said, I had familiarity with handling it because I treated my own pool in my previous home in FL and also cleaned my pool deck of all mold with chlorine diluted with water through a pump spray, as FL is notorious for mold all over due to the hot and humid conditions. I was trained from the previous owner and professional pool cleaners as I started maintaining my own pool instead of paying someone to do it.

 

Why was this old thread brought back anyway? FYI, bleach, no matter what kind, won't do the trick. Waste of time to some bad advice.
You need to do was XSleeper and Marksr advised. Only thing that will work.