Hi all ive recently set up my new predator tank 900l it hosts a silver arrowana about 7" a 15" fire eel and two 4" retics im running 3 fx6 cannister filters on it caribe sea natural marine sand. Ive been hammering the food in to feed retics seem to me eating chopped earthworm and blood worm, ive seen a big dark curly poo come out of each. Last night one of the retics looked like it had darkened in colour still active. Done ammonia test which read 1ppm, "NT LABS test kit exp 10/2016" done a 50% water change stoped feeding today. Ive brought a new API kit which reads 0 but other kit still reads 1ppm. What are your thoughts? Cheers Si