GSP in Zero-Nitrate Tank?

After some slight nitrate and algae problems several months back I decided to get a NextReef MR1 reactor with Ecobak biopellets. Slowly the nitrates have made their way down to the point where they are undetectable with a Sailfert test kit.. Ever since then (or around then) my green star polyp (which was growing like crazy) has looked pretty rough, with less than half it's polyps open and a halt in growth.

A few of my corals have suffered attacks from my peppermint shrimp, but I've never caught them on this one. From what I've heard most soft corals do very poorly in low-nutrient tanks? Could this be what is getting to my GSP?

 

Ive got undetectable nitrate in my aquarium and I have several species of soft corals that do wonderful. just started having some problems with 2 zoa colonies though. Check your Mg before you start feeding the corals to avoid a relapse of high nitrates

 

There is a difference between nitrates and nutrients. As long as your bio filter is good enough, you can have all the nutrients in the world and still have 0 nitrate. I've seen plenty of tanks with 0 nitrates and have a great amount of softies including gsp and xenia.

 

It's not clear that any coral can survive with no nitrates. Many do fine with undetectable nitrates though. GSP seems to prefer a bit more, with undetectable nitrates, the piece I had in my frag tank survived, but never actually grew.

 

I never test positive for nitrates, phosphates, nitrites etc. and I have no algae in the tank. I can't seem to get soft corals to thrive, so your thoughts could be a possible reason. My softies all open up (close from time to time) and have great coloration, but they simply do not grow much at all. I have never really been able to identify why, but my theory is too much flow (50x tank volume) and too much light. In fact, I am probably going to move my softies to shaded and protected regions, low in the tank, this weekend.

My SPS are thriving and my LPS are doing better than the softies, but not exploding like the SPS. That's why I am leaning towards my problem being too much flow and direct light.

 

I agree with Daniel. With the bio pellet reactor, you might be able to feed a little more and still keep your nitrates testing 0. I will throw out there that normally when my gsp is not opening, I discover that my powder blue has been attacking it. Tearing into the gsp seems to be his favorite stress reliever.

 

+2,in John Warner's official biopellet thread he seems to emphasize a need to feed your tank.