Anyone know what the red stuff under my rock is? I am having a hard time keeping SPS alive in a tank which is now a year old, wondering if this might be causing it. Alk is stable (7.8 dkh), phosphates are a bit high (0.09 ppm), nitrate were high but now are at 2 ppm.
One picture is just a zoomed in view of the other.
One picture is just a zoomed in view of the other.