Increasing water hardness involves adding minerals, primarily calcium and magnesium, to your water. This is necessary for various applications, including aquariums, hot tubs, and even some industrial processes. Several methods achieve this, depending on your specific needs and resources.
Methods to Increase Water Hardness
Several options exist to raise water hardness, each with pros and cons:
Using Commercial Products
- Calcium chloride: This readily dissolves and effectively increases calcium hardness. It's a common choice for adjusting water hardness in aquariums and hot tubs (source: Calcium hardness can increase in a few ways: 1) calcium chloride, 2) Cal Hypo chlorine, and 3) the water steals calcium for itself).
- Calcium hardness increasers: Professional pool and spa stores sell specialized products designed to raise hardness levels safely and efficiently (source: So fill your spa with soft water to get the purest water you can, then add calcium hardness increaser from your professional pool/spa store, to...).
- Remineralization products: These products, available at aquarium supply stores, add essential minerals to soften water, thus increasing hardness (source: You can increase your aquarium water hardness by adding crushed coral, using hard tap water, or by using remineralization products such as...). These often contain a blend of calcium, magnesium, and potassium. Seachem Equilibrium is one example (source: Using crushed eggshell or coral, Seachem Equilibrium, or sometimes just using a lot of rock in your tank).
Using Natural Materials
- Crushed coral: Adding crushed coral to the water gradually increases hardness, primarily through calcium carbonate. Begin with 1 pound per 10 gallons of water, adjusting based on your pH level and desired hardness (source: We recommend starting with 1 pound of crushed coral per 10 gallons of water. The lower your pH is, the faster it dissolves).
- Calcium carbonate (chalk): This natural compound effectively raises both general hardness (GH) and carbonate hardness (KH). A common guideline is two teaspoons per 50 liters of water (source: To raise both GH and KH simultaneously, add calcium carbonate (CaCO3). Two teaspoons per 50 Liters of water will increase both the KH and GH by about 4 dH). However, always follow specific instructions from your aquarium or system supplier.
- Eggshells: Crushed eggshells are another natural source of calcium carbonate that can slowly increase hardness.
Other Methods
- Mixing with harder water: If you have access to water sources with naturally higher hardness, you can blend your soft water with harder water to achieve the desired level. This is a simple method for aquariums and other small systems. (source: So mix distill water to your tap water to desired hardness first before replacing old aquarium water)
- Adding rocks: Certain types of rocks in your aquarium or filter can leach minerals into the water over time, gradually increasing hardness (source: Using crushed eggshell or coral, Seachem Equilibrium, or sometimes just using a lot of rock in your tank). This is a slow and less controllable method.
Important Considerations:
Always test your water regularly to monitor hardness levels. Avoid drastic changes in hardness, as this can stress aquatic life or damage equipment. Adding minerals too quickly may upset the pH balance of your water, so proceed slowly and gradually.
