I think I will monitor/test for another 4-5 days. If I dont see any spikes and all levels go to zero I will add a fish and do the same. Will start with something hardy like a hawkfish or a clown. These 3 Damsels get along well. Not sure if they will accept newbies being added to the tank or not but if I have problems down the road with these guys I will either try to catch them in the net or on a tiny hook and line(I am a fisherman haha) or introduce a lionfish and take care of that.