Elevated nitrate levels - clown fish involved...?

[scoopsthedog]

So I've had three days of elevated NO3 and I've done two days of 15% water changes. All my other levels are fine. Tank is 4 months old and stable for 3 months. I also tested the water I did the change with and it was 0 across the board.

One thing I noticed was my clown fish was disturbing a ton of sand (2" sand bed) over the last two days. Could that be causing elevated levels?

 

[scoopsthedog]

Anyone? Bueller?

 

[NickNiz]

It could be but you shouldn't have to worry about that much build up in the sand after just four months. Could leftover food be causing the nitrate spikes? If you want to knock it out I would personally do 40-50% water changes until the nitrates are in a desired range. And it wouldn't hurt to siphon the sand when doing said water changes, to remove any detritus. I hope this helps!

EDIT: I meant to do the huge water changes are way above what they should be (greater than 40 ppm). Otherwise do small water changes and siphon the sand until your levels are normal.