Urchin not doing well due to high nitrates

[hllb]

So I’m currently treating my tank with reef flux for GHA that I couldn’t get rid of. I’m a week and a half in with no reduction of gha in site. But, my nitrates are getting really high. Hard to tell on Salifert how high (I’d guess between 25 and 50 but on an API test looks like 80!). Nitrates were about 10 before this. I just turned my skimmer back on but my urchin is barely moving. He will eat some nori but he is clearly on his last leg.

So do I give up on reef flux and change the water? I’ve already lost my conch, presumably from the same issue, and a monti that was recovering. Fish and all other corals are fine.

 

[Softhammer]

Yes! Changing water will help the algae situation too.

 

[hllb]

The water changes did not help the algae before (15% each week), which is why I treated with reef flux. If I do a water change, that will stop any chance of the reef flux working. The nitrates spiked due to the reef flux treatment.