How long before I test again?

[dinotrex]

I recently added 25 lbs of liverock to lower my nitrates, so I was wondering how long after I add the liverock should I test the water for the nitrate level again?

 

[Atari]

Actually the LR will have very little (if any) effect on reducing the nitrates... it will actually produce it from ammonia/nitrites.

Nitrates are generally removed via water changes.

 

[loganj]

Was the LR cured? If not, you may want to test for ammonia/nitrites now. Adding LR to an established tank will often cause the tank to experience a "mini cycle" due to die off on the rock. AFAIK, a DSB is the only way to naturally lower nitrates and the long term viability of these is a subject of much debate right now.