The glass glue of kitchen sink become moldy in half year, how to fix?

When a lot of people do the renovation , they don't know the importance of choosing material, some people instail topmount sink with common glass glue, and it turns to black and moldy in half year,  that is so ugly, how to fix? 
  
1. If it is not too serious, you can use toilet cleaner
 
Dip in towel with toilet cleaner, and then wipe, the mold can be easily wiped off.  
 
2, scrape off the moldy glass glue  
 
Of course, if the moldy black is more serious, then you need to scrape off the glass glue.
 
First, we use a knife to scrape off the blackened glass glue from the sink counter, pay attention not to hurt your fingers.  
 
Then clean and dry the joints;  
 
Buy some mildew proof glass glue, paint again, for the kitchen such a special place, the glass glue needs to be waterproof and mildew proof glass glue.
 
Finally, wait for the glass glue till solidify.  
 
Similarly, same for the toilet.