Carbonate Hardness
Hardness is the amount of dissolved minerals such such as calcium, magnesium, iron, and zinc.
In most water it consist mainly of calcium and magnesium salts, with trace amounts of other metals.
If you water has a high concentration of minerals, it is said to be hard. If it has low levels, it is soft water.
Negative molecules that are typically found in saltwater that act as buffers are called carbonates and bicarbonates.
There is a specific kind we call carbonate hardness that you need to measure in your saltwater.
Checking carbonate harndess (alkalinity)
Measuring carbonate hardness is referred to as measuring the alkalinity. Don’t get this confused though with a pH measurement that is alkaline.
Yes, carbonate hardness affect pH, but you’re not measuring pH.
Carbonate hardness can be measured with a standard test kit. It may be called as alkalinity test kit.
It is usually reported in milli-equivalents per liter (meq/L). The level in your aquarium should be greater than 3.0 meq/L.
How to adjust carbonate harness (alkalinity)
If the buffering capacity is below the recommended level, adjustments should be made. Your pH will be decreasing as well if alkalinity is not in the normal range.
The solutions for adjusting your pH are also used to increase the carbonate hardness (alkalinity).
Water change
Use a commercially manufactured aquarium buffer.
Kalkwasser
When you remove the old water with fresh buffered saltwater (not fresh water!), the buffering capacity will increase. This is the first step.
See this page for more information on water changes.
Test the water again after about a day. If the carbonate hardness is still low, follow the next two steps.
It’s available at most aquarium dealers. It buffers the aquarium water if you use it properly. Make sure you follow the manufacturer’s instructions.
Add a solution of calcium hydroxide – kalkwasser. This will increase the buffering apacity (alkalinity) of your water.
Return from Carbonate Hardness to Most Often Tested Water Parameters
Return to Saltwater Aquarium Online Guide Main Page
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