Agree with Mr Soggy a water change and a quick test of ammonia or nitrates should do you fine. Dont worry. I reached 100 when my tank went through its inital cycle. Scary right hahaha. I didnt add any more ammonia, did a 30% water change and over time it fell. When it reached 20 I added in some clown fish and despite the fish and subsequent feeding it just slowly decreased. I was running my only my skimmer and roller mat, along with a small bag of GFO. Just be patient - a great reefing skill. Sent from Singapore Reef Club mobile app