Quigs those numbers look pretty safe ,esp if they remain there of go lower. But watch the fish, no matter what one's readings may appear to be, when the fish show distress, they are usually more accurate than the tests and you should do a water change. Don't waste your time or money on the nitrate teststing.
There is a whole lot of stuff involved here. As for ammonia and short term exposure periods - i.e. days or weeks, are different than long term or extended periods.
Depending on one's pH and tank temp. as well as the specific stock in a tank, I will often suggest that one can allow total ammmonia to rise close to 2 ppm before doing a water change. But that is another story.
As for the nitrite and salt. There are formulas to use. First off the only time ppm will be used is when you test nitrite levels (although some kits may give this in mg/L). Fortunately in water ppm and mg/L are almost identical.
The basic guideline is for every 1 ppm of nitrite there should be 10 ppm of chloride added. So we can say 10 mg/L of chloride is is needed. The simplest cheapest and most available is plain old salt, the kind you shake onto you your steak or veggies, is sodium chloride (NaCl). In fact, it is just under 2/3 chloride. So, if the goal is to get 1 mg/L of chloride into the water, we need to add roughly 1.5 mg/L of salt. As you can see this means all the rest of the volume calculation must be done in litres (stop laughing at us yanks, please).
This means if you are working in gallons, you will have to do the math to know your water volume in liters (which is how we spell litres over here). Don't forget, most tanks hold some amount less than their advertised capacity. It is your responsibility to work out a reasonably accurate approximation of the actual volume of water in your tank. For purpose of the rest of the steps, lets assume we are dealing with a tank that holds 150 L and that you have tested nitrite and its 2 ppm. So here comes the math
- 2 ppm NO2 x 10 = 20 ppm aka mgL of chloride needed. 2 x10 = 20 mg/L.
- Salt to produce 20 mg/L cl is 20 x 1.5 = 30 mg/L salt
- 150L x 30 mg/L= 4,500 mg of salt to achieve 20 mg/L of chloride
- 4,500mg/1,000 = 4.5 g of salt.
Now all you need is a scale to measure this amount. I can tell you a just measured a 1/4 level teaspoon of Mortons table salt at 2.15 gm on a tripple beam Ohaus scale. This means to handle that 2 ppm of nitrite in 150 L of water will take a hair over 1/2 teaspoon of water. Take this up a few ppm of nitrite to say 6 ppm, and the amount of salt shoots wayt up to a whopping1.25 teaspoons. As people who keep brackish or sw water tanks how salty this is.
This level of salt for the short term should not bother species normally thought of as salt intolerant. The same for plants. But if you are still worried, their are more expensive ways to get chloride into tanks. But they are not really at hand in most fishkeepers homes.
Bear in mind that it is the Na part of salt that the salt intolerant fish tend not to like. the only way to get salt out of water is via water changes. So, as soon as nitrite have dropped to 0 ppm on your kit, do a couple of big water changes over the next week or two. Remember, reducing something to 1/4 of the level it is at requires two consecutive 50% water changes or one 75% water change. etc.
