I have about 50-60 lbs of rock in salt water cooking getting ready to go into my DT. All it is, is rock and RODI saltwater with a power head. It's been cooking for about 2 weeks now, it was originally live rock I got from a friend but it was covered in bubble algae so I power washed it and decided to start over. My question is why have the got this green slime all over it and what is it?