I have had a 100 gallon reef tank with a 50 gallon sump and refugium for about 2 years. the main display tank houses LPS, SPS, Soft corals as well as some reef fish. The main readings have generally been good (PH 8.3; Calcium 430 to 440; Alk 11dkh; 0 phosphates). I have an oversized Protein Skimmer (oversized for my tank); a phosphate reactor; and live rock and sand in the refugium. But my nitrate levels have generally been between 5 and 10. I do 18 gallon weekly water changes, but I can't seem to get my nitrates down to 0. I also have increasing build up of Cynobacteria in my refugium. I previously had cyno in the main tank, but I got rid of that about 2 to 3 months ago by skimming out the substrate in the display tank. I don't overfeed my fish.
Any thoughts on how to get nitrates down to 0 and get rid of the red slime algae in the refugium. I was thinking of adding more live rock to the sump and adding calaupa. I have chetomorpha in the refugium, but the red slime is overtaking it and hasn't been doing much to get rid of the nitrates.
Any thoughts on how to get nitrates down to 0 and get rid of the red slime algae in the refugium. I was thinking of adding more live rock to the sump and adding calaupa. I have chetomorpha in the refugium, but the red slime is overtaking it and hasn't been doing much to get rid of the nitrates.