In a message dated 8/17/2002 1:03:12 PM Eastern Daylight Time, firstname.lastname@example.org writes:
The key, as far as I understand (and I'm not a chemist), is that when the pH
drops to 6.5 and lower, the biofilter's ability to naturaly rid the water of
harmfull ammonia ceases. But the fish keep adding to it via respiration and
The more acidic the water, the less ammonia a fish's gills are able to absorb. Ammonia uptake is in proportion to the pH of the water. Neutral to alkaline water is far more dangerous, from an ammonia perspective, than acidic water.