Just add salt is a bad idea! It may solve nitrite but it may cause more problems elsewhere, if the system is cycling still it could be a disaster. I will elaborate,
Cases against Soft water acidophiles and cycling systems.
To increase the water hardness, you will instead need some Epsom salt and calcium chloride. Epsom salt is the market name for hydrated MgSO4 and adding 1 milliliter of it per 10 liters of water will increase the permanent hardness by roughly 70 mg
/L CaCO3. You may however wish to increase the calcium (Ca
++) contribution to hardness as well and this can be achieved by using a marine salt mix or calcium chloride. It may feel strange to add salt to a freshwater set up, but you only have to add a really small amount of salt to increase the calcium content to suitable levels for African Rift Valley cichlids and other calcium loving freshwater species. Such a small amount of salt will not harm fish species used to hard water. Pure calcium chloride will naturally also increase the calcium content, but calcium chloride is normally must more difficult to come by than a marine salt mix. Instead of picking it up in the pet store, you may have to order it directly from a chemical supply store.
The effect of pH variation, within the range 6.5, 7.0, 7.5, 8.5 and 9, on activated sludge denitrification of a synthetic wastewater containing 2700 mg
-N was examined using bench-scale Sequencing Batch Reactors. Two major effects were observed. One, at pH values of 6.5 and 7.0, denitrification of a synthetic wastewater containing high nitrate levels was significantly inhibited. Two, denitrification was achieved at higher pH values of 7.5, 8.5 and 9.0, but the accumulation of nitrite increased significantly as mixed liquor pH increased with peak values of 250, 500 and 900 mg
-N, respectively. As the pH rose, the specific rate of nitrate reduction increased. At the same time the specific rate of nitrite reduction increased in the absence of nitrate. In the presence of nitrate the specific rate of nitrite reduction remained constant, and the degree to which nitrite reduction increased in the absence of nitrate was a function of increasing pH. While increasing pH from 7.5 to 9.0 affected nitrite intermediate accumulation, the overall time for complete denitrification (reduction of both NO−3 and NO−2) was similar for the pH values of 7.5, 8.5 and 9.
Salt will only work in a nitrate free environment and not for all fish species.
Ammonia is a nitrogen waste released by aquatic animals into the production pond environment. It is a primary byproduct of protein metabolism. Ammonia is excreted directly from the fish gill into the water. Ammonia concentrations are usually at their highest late in the production season when biomass of the cultured species and the amount of protein fed are greatest. Ammonia is toxic to aquatic life and toxicity is affected by pond pH. Ammonia-nitrogen (NH3
-N) has a more toxic form at high pH and a less toxic form at low pH, un-ionized ammonia (NH3
) and ionized ammonia (NH4+), respectively. In addition, ammonia toxicity increases as temperature rises.
The daily interplay of photosynthesis and respiration creates a cyclical change in pond pH. Pond water becomes most acidic just before the period of darkness ends and most alkaline after several hours of daylight. The presence of un-ionized ammonia, the toxic form, increases as pH rises and decreases as pH falls which causes ammonia to become more ionized. The concentration of un-ionized ammonia in production ponds is lowest just before dawn and highest late in the afternoon.
This has significant implications for water quality monitoring, especially several weeks prior to harvest when fish biomass is greatest. For example , a producer measures water quality at 0400 hr. The total NH3
-N concentration is 2.7 mg
/L, pH is 7.0, and water temperature is 28 oC. The farmer then cross-references these values with a standard, pH-temperature table and calculates the concentration of “un-ionized” NH3
-N to be 0.019 mg
/L. The producer decides to check water quality again at 1600 hr and finds that total NH3
-N is still 2.7 mg
/L. But, pH and water temperature have risen to 9.0 and 30 oC. After checking the reference table, the farmer discovers that the un-ionized NH3
-N concentration is now 1.2 mg
/L. An un-ionized NH3
-N level of 0.019 mg
/L would be considered acceptable for channel catfish production. However, the un-ionized NH3
-N concentration of 1.2 mg
/L recorded at 1600 hr could be lethal to channel catfish within several hours. Over a 12-hr period, the un-ionized ammonia concentration increased approximately 63-fold. The temperature change accounts for less than 10% of the increase in toxicity while the rise in pH from 7.0 to 9.0 is responsible for more than 90%.
The measure of whether water is acidic, basic (alkaline) or neutral is known as pH. A scale of 1 to 14 is traditionally used, which represents the negative logarithm of the hydrogen ion concentration. A pH of 7.0 is neutral; above 7.0 is basic and below 7.0 is acidic; close to 7.0 is weak and far from 7.0 is strong. It is a common perception that the pH of water is neutral and constant at a value of 7.0. In an environment free of carbon dioxide, aquatic life, and compounds other than H2O; pond pH would remain 7.0 or neutral. However, this combination of conditions is unlikely to occur on our planet. The pH of water is naturally acidic because the atmosphere contains carbon dioxide (CO2
). Carbon dioxide readily dissolves into water, raindrops and other sources of water exposed to air, forming a weak acid (H2CO3, carbonic acid). Therefore, events in the aquatic environment that affect CO2
concentrations also affect pH. There are minerals in soil that can dissolve in water to create acidity and alkalinity as well.
(Cited from various references)
.....I'm along for the ride!