hi all, i have a 3 compartments sump: (1)water in, wool filter, bio ring, skimmer ---> (2) 10 inchs DSB ---> (3) return pump
10 inch DSB in my sump, in the centre compartment, i see black coloured area in my DSB.
Why is there black colour, isit the lack of flow of water to tat part of area? isit alrite?
i have also see many 'holes' in the DSB, i assume the DSB is working and had the nitrogen(holes) converted.
is the black colour area a dangerous sign for my tank?