Are my nitrates high?

[Jason & Amber]

Just have some live rock in the tank (16 Gal) did my first water test on 5/13 had 5-10 ppm nitrates. Changed water (approx 2 Gal) checked on 5/14 still at 5-10 ppm. Could the little critters in the liverock be causing the nitrates?

[+Capt. Obvious]

Nitrate levels seem normal if you are just starting out. The cycle takes a bit to get started. In addition, smaller tanks can be more difficult to maintain water quality. Also, what test are you using?

[Jason & Amber]

API reef master kit just changed water and retested looks like it may have came down to 5 ppm.

[Timfish]

I would not worry about it. Considering the API is marked off at intervals of 10 ppm gauging the in between readings is going to have an element of inacuracy. The test kits that turn red instead of brown are going to be a little more accurate but nitrates need to be fairly high before they really cause problems and like Capt. Obvious pointed out at this point in setting up your tank it's almost to be expected. I would also point out with a water change of 2 gallons in a 16 gallon system you would have only removed 12% of the nitrates so if you had 10 ppm it would have only dropped to 8.8 ppm. You would need a very sensitive test kit to detect that small of a change. As there are animals that will add or remove nitrates readings can change without doing a water change and a water change may not always produce the expected drop.