I've been trying to lowering my nitrate level with frequents water change and decreased feeding on my 15 gallon nano but it barely have any affect on them, the phosphates was normal at 0.03 ppm but the nitrate was at 50 ppm. I haven't got an algae problem yet, but few corals are closed particularly the zoas. The nephtheas seems unbothered and the toadstool have been closed for weeks now, idk if that happened bcs of the nitrate spikes or just their natural habits. I only got two fish in there (Banggai cardinal & yellow watchman goby).
I noticed something that maybe the culprit of the nitrate spikes. In one of the rocks I keep seeing a detritus accumulation in that particular spot, I always clean that area when water change but few days later it already filled with detritus. When I observing it closely, I noticed that the detritus was coming FROM THE ROCKSS, there's something that shoots poop from tiny hole in the rocks. I don't know what critters did this but I want to get rid of it.
Soo any idea what that is and how can I stop it from shoots more nasty stuff in my tank, I don't want to throw the rocks tho, and should I begin dosing to drop my nitrate?

I noticed something that maybe the culprit of the nitrate spikes. In one of the rocks I keep seeing a detritus accumulation in that particular spot, I always clean that area when water change but few days later it already filled with detritus. When I observing it closely, I noticed that the detritus was coming FROM THE ROCKSS, there's something that shoots poop from tiny hole in the rocks. I don't know what critters did this but I want to get rid of it.
Soo any idea what that is and how can I stop it from shoots more nasty stuff in my tank, I don't want to throw the rocks tho, and should I begin dosing to drop my nitrate?
