Test Kits Test kits are available for pH, ammonia, nitrite, nitrate, oxygen, carbon dioxide, phosphate, iron, hardness, alkalinity, chlorine, and more. The most important test kits to have are those for pH and ammonia. The next important are nitrite, nitrate, and hardness. The other kits are more important for people with planted or marine tanks. Test kits may no longer work properly past their expiration dates so check those before using a kit.
Most kits register a color change for comparison against a chart.
The acidity or concentration of hydronium cations in the water. 7 is basic. The pond is 5 feet wide by 10 feet long by 3 feet deep. Since 1 g water takes up 1 mL, that means 0.1 g salt per 100 mL water or per 0.1 L of water. Since 1 gallon of water is 3.785 L, then 1 L is 0.2642 gallons.