First water tests and ammonia dosing

Last night, while I was filling the aquarium with water, I also set aside a glass of the same, not dechlorinated, tap water. I did this because tap water readings are not reliable if tested as soon as the water is drawn from the tap. On the other hand, tap water parameters can be very useful as ammonia and nitrite is sometimes present in poor water supplies, it is also useful to know the pH and hardness, to better understand the buffering capabilities of the water. The results were as follows:

  • KH: 9 ° (161.1 ppm)
  • GH: 18 ° (322.2 ppm)
  • ammonia: 0 ppm
  • nitrite: 0 ppm
  • nitrate: 0 ppm
  • pH: 8.0

From those results, I can see that my tap water is quite hard but generally quite good quality. There are two pH tests included in the API kit: the “mid range” test gives a reading only up to 7.6 and the result was 7.6, while the high range test starts at 7.4 and the result was 8.0. From this, I can see that the value is higher than the mid range test will show, so I disregard that and use 8.0 as the correct result.

Next, I tested the aquarium water. I expected this to be almost identical, but with slightly higher ammonia. Test results were as follows:

  • KH: 9° (161.1 ppm)
  • GH: 18° (322.2 ppm)
  • ammonia: 0.25 ppm
  • nitrite: 0 ppm
  • nitrate: 0 ppm
  • pH: 8.2

My guess was correct: because my tap water contains only chloramine (NH2Cl), no chlorine, the dechlorinator will leave ammonia (NH3) and ammonium (NH4+) behind, after rendering the chlorine harmless. Ammonia is toxic to fish, so if doing large water changes, it is important to use a dechlorinator which will “deal” with it, leaving predominantly the less harmful ammonium. The pH reading for the aquarium water was higher than tap water, but I will still consider it to be no different because the kits are not particularly reliable.

Temperature is at a steady and favourable 28.5 °C, so I dosed the aquarium with 2 ml of 9.5% ammonia at 8:30, which has given me a 4 ppm reading.

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