nitrate spikes in coral tank issues

[fleecemist]

I'm new to this, but could it be something dead in the tank? Like a snail or something?

[Kaidox]

Nah, dead stuff usually spikes ammonia first. Nitrates come later. But good thought, man.

[skylark]

If you're running carbon, check that too. Old carbon can release organics back into the water column.

[flinta]

If it's a sudden spike, consider a water change with fresh salt mix. I use Tropic Marin Pro and it's kept my nitrates stable in my 120-gallon.

Second this. A 20% change with a quality salt mix can work wonders. Just match temp and salinity carefully.