My tank has the uglies...

[g5flier]

System is now 6.5 months old and just recently seeing some nasty brown algae (not red ) growing on the bottom of the tank. Not seeing any on my rocks, but if you look closely at the photo you can see it on my monti frags.

Red Sea test kits show Phosphate as 0.02 (max, likely under this) and Nitrate as 4ppm. PH 8.1 - 8.2, temp 78, Salinity 1.026, Alk 9.0, Calcium 420, Mag 1350. I do a 10% water change every 2 weeks w/BRS RO 4 stage. System is 159 gallons total. 3 Radion's run 7 hours of 19K followed by about 3 hours of blues for viewing. I discontinued Red Sea Reef Energy A&B about a week ago but nothing changed since then, my fish feeding habits haven't changed and no new additions in months. Just started a 20 gallon refugium to help overcome this, but its only been running a few days.

I would have thought my system was past the diatom bloom stage, any ideas what it is and how to over come, or just be patient and wait for it to go away. Thanks!!!

 

[jsker]

Diatoms like Phosphates, and silica. I would suggest picking up a different brand test kit to compare your phosphates. I thought my phosphates were in line until I compared my test with low range phosphorus checker and found my phosphates were very high. Also when algae is present our systems nutrient levels test lower then they really are for the reason the algae is consuming the nutrients.

Check you RO filter, if the filter is filtering faster then is used to then your filter need to be replaced.