I have a 150 gal tank,i will admit it was a bit overstocked.So i get rid of most of my fish,but the yellowish water persists(even after replacing half of the tanks water)plus it had a very bad smell to it,since the water change it doesnt smell so bad.The ph is 7.0.I change the filter media every week or so.What could be causing this???Any help is appreciated.
