Water quality refers not only pH, EC, turbidity, carbonates, etc., but all of those things in combination. Most aquaponicists think that if you line all of the variables up (media, plants, fish, microbes), then everything will work out. Read more: http://podcast.brightagrotech.com/episode-20-water-quality-in-aquaponics
In many instances, however, this is not true. Oftentimes, when it doesn’t work out quite right, it comes down to small water quality problems. Even if the problem is small, the results can be big because water affects everything in your system.