It’s time for everyone’s favorite topic: water quality!
Many of our clients purchase “master” test kits which include: ammonia, nitrite, nitrate, low and high pH. This is a great collection of parameters to start with, but what about kH?
For those of you unfamiliar with kH, kH measures the buffering capacity of your water. Buffers bind to free hydrogen ions (H+) and keep them out of solution. Since your pH is a direct measure of [H+] in your system, kH directly impacts pH. And remember that high [H+] = more acidic and low [H+] = more basic.
(For those of you who are confusing this with gH, or total hardness: gH measures the amount of calcium and magnesium in your water. Although this may be a component of your kH, they are separate parameters entirely.)
So, if your kH levels are too low, all the H+ your fish discharge due to metabolic processes can build up and crash your pH. Adequate kH levels will keep your pH consistent throughout the day, regardless of what your fish and filters are doing. Knowing your tanks kH is an essential component to any fish keeper’s database. There are simple tests available that will make your testing a true “master kit.”
A kH value of >50 mg/L is adequate, but >100 mg/L is better.
If your tank kH is low, test your source water kH. Some city and well systems have low kH coming in and will need buffers to be manually added to your system to maintain adequate levels. Keep an eye on your pH when manually adding buffers in order to make sure your pH will not change too much. Slow and steady is the goal for any pH changes.