yeah it looks to be algae to me. my cats also get this stuff on the water bowl and i even get it in the bath tub. i could definitly be wrong though as i have no experience with resevoirs but if it is algae then make sure your resevoir is light proof.
michaelpeg Reviewed by michaelpeg on . 2 Dumb Questions I should know I have a 5 gallon bucket with an air pump running 24 hs with fow farm grow big and big bloom. There seems to a red preciptate that collects at the bottoom ( see pic). Also is there a point in bubbling water to purify water. I can't afford R/O or distilled in the quantity needed Rating: 5