in my JBL booklet it says "Increased ammonium or nitrite levels are always an indication of a disturbance in the bacterial decomposition process or poisoning of the nitrifying bacteria. This may have different causes such as excessive feeding, overstocking with fish, insufficient oxygen content, medication, changes in pH values etc". That makes me think that perhaps it's the cycling that is in a bung spot. It has converted the ammonia to nitrite but hasn't moved it to nitrate stage yet. Maybe a properly cycled filter from another tank in some angel friendly water is the answer. Or maybe that's what you've done already :dunno: