Reducing Nitrates w/o Water Change?

I'm on the 14th day of my tank cycle and my nitrates peaked at 25ppm two days ago and now they are down to 2ppm. Other than water changes, how are nitrates reduced? My tank is setup with live sand and a small amount of live rock seeding 70lbs of dry rock.

 

Macroalgae such as chaeto will reduce nitrates. Also large amounts of live rock and deep sand beds. The bacteria that changes nitrates to nitrogen gas do not like oxygen so they are in deep crevices of live rock and deep in sand beds.

 

not necessarily a lot of live rock but a lot of rock with deep pores.

 

I only have about 10lbs of live rock, the rest is Reef Saver rock from BRS. I'm using live sand, but it's only about 2 inches deep.

 

On the surfaces of the aquarium you get a film of bacteria. At the lower levels of the film you get lower oxygen levels. When O2 is low, certain bacteria is able to use nitrate, instead of oxygen to oxidize carbon. The result is nitrate is converted to nitrogen gas and is diffused out into the atmosphere. Also, some algae and bacteria will take up some nitrogen for tissue growth. This isn't really removed from the system though, unless the organism is removed. It is locked up though, and no longer "testable".