Ok I have a 125, mildly stocked with a 55g sump doing aprox 2000gph. No matter what kind of food I feed, Minutes later my tank smells like rotten fish. I've had tanks for 14yrs now and have never experienced this. nitrites,nitrates, ammonia all at 0. I don't overfeed. the tank does not get direct sunlight and only has 20w of LED lighting during the day. Help before my wife kicks me and the tank to the garage