New tank start up (16 days in) and brown spots are starting to cover EVERYTHING. Sand (washed pool filter sand) is turning brown and brown spots on everything in tank. I assume this is the diatoms (or brown algae) that people experience on new tank set ups? Maybe from silica in sand? From my research here I assume just let them be and eventually it will go away? Dont want to scrub anything because I am trying to get my BB going. I guess that is my question - they eventually go away?