pH is a measure of how acidic or alkaline the water is in your reef tank. It is important to maintain a stable and optimal pH level for the health and growth of your corals and other marine life. The ideal pH range for a reef tank is between 7.8 and 8.5, with 8.3 being the optimal value.
However, many factors can cause the pH to drop below this range, such as poor ventilation, carbon dioxide buildup, calcium reactor use, organic waste accumulation, and low alkalinity. In this article, we will explain how to raise the pH in a reef tank using some simple and effective methods.
Aerate the Water
One of the easiest ways to raise pH in a reef tank is to aerate the water by increasing the oxygen concentration. This process in turn lowers the carbon dioxide concentration, which is generally acidic and responsible for producing more carbonic acid. Carbonic acid lowers the pH by consuming bicarbonate and carbonate ions, which are the main components of alkalinity. By aerating the water, you can reduce the carbonic acid level and increase the alkalinity, which will raise the pH.
There are several ways to aerate the water in your reef tank, such as:
- Using a protein skimmer, which produces fine bubbles that exchange gases with the water.
- Increasing the surface agitation of the water using powerheads, wavemakers, or air pumps.
- Adding more live rock or macroalgae, which produce oxygen through photosynthesis.
- Pulling air from outside and directing it into the skimmer or airstone, provided that the outside air has a lower carbon dioxide level than the room air.
Another common way to raise pH in a reef tank is to use kalkwasser, which is a saturated solution of calcium hydroxide. Kalkwasser has a very high pH of around 12, and when added to the tank water, it reacts with carbon dioxide to form calcium carbonate and water. This process removes excess carbon dioxide from the water and increases the alkalinity and calcium levels, which are beneficial for coral growth.
Kalkwasser can be dosed to your reef tank using a kalkwasser reactor or a dosing pump. A kalkwasser reactor is a device that mixes RO/DI water with kalkwasser powder and drips the solution into the tank. A dosing pump is a device that delivers a precise amount of liquid to the tank at regular intervals. Both methods require careful monitoring of the pH, alkalinity, and calcium levels to avoid overdosing or underdosing.
The next way to raise pH in a reef tank is to use buffers, which are substances that resist changes in pH by releasing or absorbing hydrogen ions. Buffers can be added to the tank water to increase the alkalinity and raise the pH. There are many types of buffers available for reef tanks, such as:
- Sodium bicarbonate (baking soda), which raises both alkalinity and pH.
- Sodium carbonate (soda ash), which raises both alkalinity and pH more than sodium bicarbonate.
- Calcium carbonate (crushed coral or aragonite sand), raises both alkalinity and calcium but has a slower effect on pH.
- Commercial buffer products may contain various ingredients to raise alkalinity and pH.
When using buffers, it is important to follow the instructions on the label and test the water parameters before and after dosing. Buffers should be added gradually and sparingly to avoid sudden swings in pH or alkalinity.
Use CO2 Scrubbers
Another way to raise pH in a reef tank is to use CO2 scrubbers, which are devices that remove carbon dioxide from the air before it enters the tank. CO2 scrubbers are usually attached to protein skimmers or air pumps, where they filter the incoming air through a media that absorbs CO2. The media can be soda lime, zeolite, or other materials that change color when saturated with CO2. By using CO2 scrubbers, you can reduce the amount of carbonic acid in the water and increase the pH.
CO2 scrubbers are effective but also expensive and require regular maintenance. The media needs to be replaced frequently depending on how much CO2 it absorbs. The media can also release heat and moisture into the air, which may affect the temperature and humidity of the room.
Use Reverse Osmosis/Deionized (RO/DI) Water
The last way to raise pH in a reef tank is to use reverse osmosis/deionized (RO/DI) water for top-off and water changes. RO/DI water is water that has been purified by passing through multiple stages of filtration that remove impurities such as chlorine, metals, minerals, organic compounds, and bacteria. RO/DI water has a neutral pH of 7 and very low alkalinity, which means it can easily adjust to the pH and alkalinity of the tank water. By using RO/DI water, you can avoid adding tap water or bottled water that may contain substances that lower the pH or alkalinity of your tank water.
RO/DI water can be purchased from local fish stores or online vendors, or you can make your own using an RO/DI unit. An RO/DI unit is a device that connects to your faucet and produces RO/DI water on demand. An RO/DI unit requires regular maintenance and replacement of the filters and membranes to ensure optimal performance.
pH is a crucial parameter for reef tanks that affects the health and growth of corals and other marine life. The ideal pH range for a reef tank is between 7.8 and 8.5, with 8.3 being the optimal value. However, many factors can cause the pH to drop below this range, such as poor ventilation, carbon dioxide buildup, calcium reactor use, organic waste accumulation, and low alkalinity. To raise pH in a reef tank, you can use one or more of the following methods:
- Aerate the water
- Use kalkwasser
- Use buffers
- Use CO2 scrubbers
- Use RO/DI water
These methods are simple and effective, but they require careful monitoring and adjustment of the water parameters to avoid overdosing or underdosing. It is also important to maintain a stable and consistent pH level rather than chasing a specific number. By following these tips, you can raise the pH in your reef tank and create a healthy and thriving environment for your corals and other marine life.