Ammonia Level at 0.25

Hi,

I’m quite new to marine fish keeping. All of the water parameters were spot on and the cycle completed correctly. For the past 24 hours my ammonia level has risen from 0 to 0.25. Nitrites have remained at 0 and Nitrates are around 20 or slightly lower.

Is this safe or should I perform more water changes? Last night I performed a 10% water change and this has not helped.

I think I overfed the aquarium which caused the ammonia to rise. Is this the cause or has something else caused it?

Details of my aquarium are:

Redsea Max Nano (75L) – Dry rock, live sand, Nutri Seawater.
2 clown fish – added 9 days ago
4 hermit crabs – added 3 days ago
3 Zoa coral frags – added 2 days ago

Any help will very much be appreciated.

Many thanks,

Phil