I get the impression that most aquarists know the gist of why we test our tank water during the initial aquariums cycle, for ammonia, nitrite, and nitrate, but not later on after the tank is humming along.
Beyond the cycle, the tests become just numbers, and some may not realize their significance.
Testing after the cycling is done, is important to help determine water change schedule, and amount of water we change.
We also test after adding more fish, or plants, because this can temporarily or permanently change our water change routine.
Most of the time, our "tap" water will be fairly consistent, if from a large lake, or well (although it may not if our water source is a river that changes, with the seasons, or is a well influenced by agriculture)
But our tap water controls all, so every aquarist should learn its parameters.
Testing before and after water changes is very important.
It is the difference between before and after, that is most telling if our water change routine is sufficient.
Every tank is different, so although there are generic rules out there, many may choose to follow about water changes, your tanks may be radically different (especially when trying to house monster fish)
Most of the water change rules, and filtration norms (manufacturer specs) are based on a community tank of a few tetras, an angel fish, and some cory cats, "not" on 6 oscars, or 2 stingrays, or an Arowana.
If the water in the tank has drastically different water parameters just before a water change, than after, it means out water change schedule is probably not adequate, and volume not enough.
If after a water change pH is 8, but before is 6, it means the time during between water changes has allowing the water to acidify with fish urine, or other metabolism by-products. So more frequent water changes are needed to bring those two pH numbers closer together.(8 before, 7.6 after, is reasonable)
If after a water change your nitrate reading is 5ppm, but "before the water change" it was 40ppm, it also means there has been too much time lapse between water changes, and not enough cleaning of filter media. A more reasonable difference might be 5ppm nitrate after, 15ppm before.
Adding new fish may also change our parameters, a neon or 2 may not make a bump, but a new 6 inch oscar can turn a tanks urine soup mix upside down and require a doubling in frequency of water changes and frequency.
Testing the difference in pH and nitrate soon after adding that oscar is like the canary in the coal mine, if pH drops significantly, or nitrate increase, from the norm, your new purchase has just forced a change in your routine.
The buffering capacity (alkalinity) of your tap water may have a significant influence on water parameter disparity, which may mean even more frequent water changes are needed.
Beyond the cycle, the tests become just numbers, and some may not realize their significance.
Testing after the cycling is done, is important to help determine water change schedule, and amount of water we change.
We also test after adding more fish, or plants, because this can temporarily or permanently change our water change routine.
Most of the time, our "tap" water will be fairly consistent, if from a large lake, or well (although it may not if our water source is a river that changes, with the seasons, or is a well influenced by agriculture)
But our tap water controls all, so every aquarist should learn its parameters.
Testing before and after water changes is very important.
It is the difference between before and after, that is most telling if our water change routine is sufficient.
Every tank is different, so although there are generic rules out there, many may choose to follow about water changes, your tanks may be radically different (especially when trying to house monster fish)
Most of the water change rules, and filtration norms (manufacturer specs) are based on a community tank of a few tetras, an angel fish, and some cory cats, "not" on 6 oscars, or 2 stingrays, or an Arowana.
If the water in the tank has drastically different water parameters just before a water change, than after, it means out water change schedule is probably not adequate, and volume not enough.
If after a water change pH is 8, but before is 6, it means the time during between water changes has allowing the water to acidify with fish urine, or other metabolism by-products. So more frequent water changes are needed to bring those two pH numbers closer together.(8 before, 7.6 after, is reasonable)
If after a water change your nitrate reading is 5ppm, but "before the water change" it was 40ppm, it also means there has been too much time lapse between water changes, and not enough cleaning of filter media. A more reasonable difference might be 5ppm nitrate after, 15ppm before.
Adding new fish may also change our parameters, a neon or 2 may not make a bump, but a new 6 inch oscar can turn a tanks urine soup mix upside down and require a doubling in frequency of water changes and frequency.
Testing the difference in pH and nitrate soon after adding that oscar is like the canary in the coal mine, if pH drops significantly, or nitrate increase, from the norm, your new purchase has just forced a change in your routine.
The buffering capacity (alkalinity) of your tap water may have a significant influence on water parameter disparity, which may mean even more frequent water changes are needed.
