Hey guys just cycled a used tank i bought off craigs list. its a 220 gal. used water from other tanks to cycle it and many established items to help the process along. it cycled with green terrors for for 8 weeks then i added the rest of the fish. i was doing my weekly water change when i noticed these little white things covering everything, glass, black overflows, plants, and heavy on my wood. they scrape off easy from the glass and atm i am trying to get rid of the black crap that grows on broad leaves which i would love input on how to avoid and get rid of that stuff as well. thanks any info is welcome here are some pics. thx