My nitrates have always been between 5-10. Now suddenly the nitrates are resting at about 20-30.

I know this isn't anything to panic about... yet I am. I have had some changes to the tank. I found new homes for a pair of clowns and a large tang. I *think* I adjusted feeding accordingly. I also rearranged all the rock, took out a few pieces and put in a few new ones. And, I added another 20lb of sand.

When I saw the nitrate rise I changed 25% of the water. No change in nitrates. Another 25% a few days later, and another 25% a few days later, and another... Still, no change in nitrates. Also tried a nitrate reducing media, knowing its probably just a gimmick but willing to try... no change so far.

I'm starting to be suspiscious of my year-old API nitrate test kit. Unfortunately no one seems to have the salifert in stock until Nov 1. Could it be that the rock and sand changes are causing some nitrate spikes and my water changes only kept it in check without reducing it?

During this time, every tank occupant is looking healthy and extended. Even the "rescue" corals are showing new growth and the "difficult" corals are showing polyp extension. I have no SPS. All softies, LPS, and a few NPS. So how concerned do I need to be?