Originally Posted by ExtremeBoss
The pH of my water is 6.4.
The common aquarium “ammonia” test measures the total ammonia, both ionized and un-ionized (Total Ammonia Nitrogen or TAN).
toxicity, where the ammonia kills slowly by a variety of mechanisms, is as follows:
- 20 to 100 ppm of ammonia TAN at a pH of 6.0
- 2 to 10 ppm of ammonia TAN at a pH of 7.0
- 0.2 to 1 ppm of ammonia TAN at a pH of 8.0
Any pH between the above numbers you will have to make a linear interpolation. As you can see there is a 10 times increase or decrease in toxicity between pH levels.
A pH of 6.5 will reduce the growth of beneficial bacteria by 90%. A pH of 6.0 will virtually stop beneficial bacteria from oxidizing ammonia to nitrate; hence ammonia may be on the rise.