i use to use the bleach water combo. now i just powerwash all my tubs then hose them out and let them dry. i don't know i guess the warning labels on the dimension 3 kinda made me worry since i can kill stds within 10 mins pending on what it is like syphilis kills in 3 mins, the hiv/aids virus it kills in 10 mins. and it named a bunch of other ones and warns not to use near animals or pets.