That's actually a type of Red Algae. Check your nitrate and phosphate levels. Make sure you are not adding anything that contains phosphates such as some PH stuff. Also you if your lighting is on too long or your take is near a window or somewhere where sunlight is getting to the tank that would do it. The Red/Dark algae is almost always the first algae to start growing.live2bet said:Just set up my brand new xP4 for about a month and 1st 3 weeks was just for fishless cycle and the last 1 week had only 1 5" oscar in it and now the inlet and outlet tubing is covered with spots of black stuff.
Anyone knows what is the problem?
ps. xP4 is in a 135g tank with 2 AquaClear 110.