Its just part of the natural cycling that takes place with a new tank. Just be paitent. A refugium would be helpful. Make sure your skimmer is working efficiently. The only other thing I might suggest is running some activated carbon but until the system finishes cycling that may be counter-productive.

The nitrates are going to feed the bacteria that are needed for a mature system. The development of those bacteria are the final step in the cycle. Just give it some time.

Gary