Ammonia spiked out of nowhere
Hello everyone. Up to jan 25 my ammonia and nitrate levels were fine. Today jan 27 they're off significantly. Amm is 2.0ppm and nitrates are 40ppm.
I do 20% water changes every 2 weeks and things have always went well.
On jan 14- 15 I added a few more inhabitants. 1 spotted sweetlips, 1 yellow tang, 2 coral beauty angels, 1 sea hare, pin cushion urchin, and 1 red ridge coral. Earlier in the month I've added two anemones and one them split and moved further away from the other. My tank is very clear and there's no smell.
I also added a seaweed clip and add seaweed to it often.
For added nutrition I added saltwater plants called Halimeda.
My tank and fish never looked so beautiful. None of my fish are missing and my anemones look healthier than ever. One of them finally came out of hiding.
I'm preparing my water to do a 50% water change right now.
Is there anything I'm missing from diagnosing the problem with the ammonia and nitrate spike?
I appreciate any help.