pH, kH, and gH
Monitoring pH in an aquarium indicates the moment when water should be changed or when to siphon the substrate. Excessive waste generates carbonic acid and reducing water pH value. Water hardness is very important for fish, having a major effect upon water pH and water stability, as well as on the fish osmoregulation - vital in maintaining fish health. According to data, fish survival rate is 100% for a hardness value of 140 - 180 mg/L and 94.5% for a hardness value of 250 mg/L. In the case of high values for water hardness, death rate increase is not significant, but it occur unpleasant effects upon young's growth and reproduction where the hatching rate is very small. The first noticeable sign is spawn whitening. Magnesium in water reveals, a survival rate of 100% for a concentration of 50 mg/l and 98% for a concentration of 120 mg/l. Magnesium concentration in water is highly related with calcium concentration, both influencing water hardness.
Calcium has a complex role for both aquatic organisms - by entering in their bone structure and participating to their metabolism, and for plants - by participating to the photosynthesis process. It also influences, along with magnesium, water hardness.
According to the results regarding calcium concentration in the tank, the survival rate was around 100% for a 150 mg/l concentration, 98.5% for a 200 mg/l concentration and 92% where calcium concentration is 300 mg/l.
In the case of the waters with a high calcium and magnesium concentration level (high hardness level), there can be noticed, especially in young fish, an early
bones' ossification, they cease to grow and they don't reach sexual maturity because of their undeveloped genital apparatus.
Ammonia concentration in water is related to water pH and temperature. For the water with low levels of both pH and temperature, ammonia maximum admitted limit is significant higher than the one in the water with high pH and temperature levels.
Concerning the nitrates, fish survival rate is approximately. 100% for a 5 mg/l concentration, 97% for a 70 mg/l concentration and 89% for a 100 mg/l concentration.
Concerning the nitrites, the survival rate is approximately. 100% for a 0.03 mg/l concentration, 98% for a 0.1 mg/l concentration and 75% for a 0.3 mg/l concentration.
Nitrites and nitrates to a lesser degree in high concentrations leads to fish' behavior changes: side swimming, water piping, bottom sitting and possible death.