What am I fighting?

squarereefer · Nov 29, 2024

My mixed reef tank is 18 months old and has been mostly trouble free. I suffered a major algae outbreak In October which to the best I could tell without a microscope was Dinos. The assumption was made based on the fact that my nutrients were completely bottomed out 0 nitrate 0 phosphate and the algae had snotty looking bubbles. I slowly raised Nitrate to 10 ppm and Phosphate to .08 ppm by dosing NeoNitro and feeding heavier than normal. I also lowered my lighting intensity and shortened schedule. Once nutrients were stable in that range, I went for a 3 day blackout on the tank which seemed to be successful. At the end of the period all signs of algae were gone and the sand bed looked pristine.

Post blackout - I returned to my reduced lighting schedule and the tank looked great, minus some SPS that came out of blackout looking a bit ticked off. I have been slowly ramping it back up to my normal intensity/photo period (not fully there yet) but unfortunately I noticed some dark spots on the sand Wednesday , that seem to growing in to a hair algae which I assume will end up looking just like the "Dinos" from pre black out. I also noticed some brown stringy algae reappearing on my Sentosa which was covered in the presumed Dinos pre-black out.

Current Parameters: Tank Temp: 78, PH 8.6, Phosphate .05ppm, Nitrate 12ppm, Calcium 430ppm, Alkalinity 8.7, Magnesium 1300.

What am I dealing with? Would it still be Dinos given the tank has had stable amounts of nutrient for weeks now? I plan to refresh my clean up crew tomorrow but I am hesitant to drop $50+ worth of snails if this is toxic algae.

ChrisRD · Nov 29, 2024

I've had dinos in tanks without N and P bottoming out, so I wouldn't rule it out based on that. Looks like dinos in the pics. If it's ostreopsis (seems to be the most common) UV is effective. I've also run fine filter floss in the sump and rinse it each morning (they get caught in it at night when they enter the water column) which seems to help too. No experience with other dino types...

squarereefer · Nov 30, 2024

Thank you for the info Chris. If this is the same thing I dealt with last month, it is whatever variety of Dino that sticks to rocks and sand and does not get into the water column easily so that my UV can zap it. I forgot to add that I replaced the lamp in my Aqua UV 7w sterilizer and installed a new pump for it to make sure that I had proper flow during the battle last month. I have been running without filter socks or floss in my sump but that is a great idea and I'll give it a shot to help catch anything that does make it into the sump.