I started my sps tank a few weeks ago with cooked live rock and live sand. One week after starting the tank, nitrates were at 2.5. I just check it today, 4 weeks later, and it's still 2.5. I had a diatom outbreak which resolved but now I have small areas of hairy/bubble algae growth. On a hunch, I tested my RO/DI unit which is 2mos old, and the nitrates are 2.5 as well. Sorry, I don't have a TDS reading. I'm currently running carbon, purigen, and phosgard. Is there any way to lower the nitrates coming out of my Ro/Di unit? Bioload= 2 chromis. Options: i guess i can buy ro/di water and add some chaeto but i really want to make use of the ro/di unit. thanks and sorry for the long post.