Brianna

If presented with an unknown carbonate precipitate, how could I determine if it is calcium carbonate, sodium carbonate, or potassium carbonate ?

I had a goldfish in a 2gal tank with no gravel or base medium, and only an air-stone bubbler with sponge on it for bacteria. I scraped brown growth & siphoned the poop once a week, I had no plants or green algae. (only had led lighting). I would test the water, every 4 weeks after things settled for pH and Nitrates. I would add small amt of eggshell to buffer pH and do partial water changes every 2 weeks. pH 7.2 and nitrates 75ppm. In 3 years, the fish died and was discarded. I left the tank operating. Two months had gone by before I decided to get new fish. I tested the water first, & pH was 8.2 and the Nitrates were 0 ppm. Nitrates disappeared? Puzzling ? (Tested nitrate reagents on friends tank - reagents were ok.) Since the bubbler was always on .. the question is .. What happened to the Nitrates in an aerated but recently vacated fish tank??

What happens to the concentration of Nitrate in hard water, as the solution is boiled down to 50%, 80%, and 99% of its original volume respectively? Does nitrate concentration increase? Does nitrate evaporate out with water? Will it precipitate out?