Last Updated on July 19, 2021 by Marco C.
If you notice white salt precipitates in your system, these are signs of calcium buildup. Although calcium is not dangerous for your plants and fishes, it is an indicator for nutrient imbalance in your system. Aquaponics maintenance is crucial in ensuring that the system operates efficiently and reduces the risk of your system failing. There are several ways on how to remove calcium buildup in fish tanks. Before we discuss how to clean calcium off your fish tank, we need to ask;
What Causes Calcium Buildup In Fish Tanks?
pH Levels Of Above 7.5 Create Insoluble Calcium Carbonate Precipitates
Basic water naturally allows for calcium carbonate to precipitate as salts. These white salts form as mineral deposits in the surfaces and crevices of your fish tank. The reaction between calcium and carbonates stand at an equilibrium depending on the pH levels. A higher pH will let the reaction-forming salts occur more. This leads to more calcium precipitates than calcium ions available for plants.
Bicarbonate Concentrations Of 120ppm and Above Are Susceptible To Calcium Carbonates As Well
An abundance of carbonates in your system will also form precipitates from its reaction with calcium. High concentrations of carbonate force more calcium ions to bind with carbonate, forming more precipitate on surfaces. This increase in carbonates could come from using hard water. Another reason for higher bicarbonate concentrations would be from evaporation of water and transpiration of plants. These two natural processes reduce the amount of water in your system while leaving the nutrients in the system including the bicarbonates.
Less Carbon Dioxide In the Water Leads To Calcium Precipitate
The equilibrium between soluble calcium ions and calcium carbonate precipitate is influenced by carbon dioxide. As carbon dioxide concentration in water decreases, more precipitates will form. The amount of carbon dioxide is affected by photosynthesis of algae or increase of water temperature. As calcium reacts with bicarbonate to form calcium carbonate and carbonic acid, the reverse is also possible. Water, on the other hand, reacts with carbon dioxide to form carbonic acid. The equilibrium reaction between the two chemical equations affect each other significantly. As carbon dioxide in the water decreases, this will lead to less carbonic acid to react with calcium carbonate to dissolve, leading to more salt deposits.
Water Temperature Rising Makes Calcium Ions React With Carbonates
High water temperature speeds up the reaction and binding of calcium ions to carbonates. This forms precipitates for calcium carbonates faster and causes buildup to occur. Higher water temperature also leads to more evaporation, increasing the overall concentration of ions. Carbon dioxide concentrations also decrease leading to more formation of calcium carbonate.
How To Remove Calcium Buildup In A Fish Tank?
Lower pH Of Water To Remove Calcium Buildup In The Fish Tank Naturally
Calcium carbonate salts will naturally dissolve over time if your water pH is slightly acidic. Though this may take time, there is no harm done to plants and fishes from calcium carbonate deposits. Naturally, this may be more of an indicator of overall tank health and pH balance. Treating the problems at the root cause is the best way to ensure the sustainability of your setup. This will slowly remove the calcium buildup in your fish tank.
Drain The Tank and Use Weak Acids Like Vinegar Or pH Down To Scrub The Calcium Carbonate
As calcium carbonate dissolves in acidic solutions, using vinegar or pH down will work. Personally, I do not suggest doing this with your fish and plants still in the system as sudden change in pH will cause them stress. After removing the calcium buildup from the fish tank, douse the spot to wash the acid off before reintroducing the fish and plants into the system. Avoid using citric acid as this is a natural herbicide which could possibly harm your plants.
Proper Aquaponics Maintenance Prevents Calcium Buildup In The Fish Tank
Add Water Daily To Compensate For Evaporation and Transpiration To Lower Concentration Of Carbonates and Calcium
As water evaporates and plants transpire, you lose water but not nutrients. This increases the concentration of your aquaponics water over time. Adding water to compensate for daily water loss is important. Make sure the water is prepared beforehand if using hard water to make sure that you aren’t adding more calcium carbonates into the water. This can be easily measured by water height in each component.
Aquaponics Maintenance Should Keep pH Below 7 With A Steady Decrease Over Time
Calcium carbonate dissolves in acidic water, reducing the buildup of calcium carbonate precipitates. Aquaponics water naturally acidifies over time due to nitrogen-fixing bacteria. This is an indicator of a healthy aquaponics system. With proper maintenance and nutrient balance, you will notice a slow decrease in pH. As calcium carbonate buildup occurs in waters that are basic, there should be less occurrence of this in aquaponics. Maintenance of aquaponics involves proper feeding rates and making sure components are working at operational capacities. If your water turns basic or forms calcium carbonate precipitates, it would mean a lot of nutrients are not available for the plants.
Avoid Direct Sunlight For The Fish Tank and Water Surfaces To Avoid Algal Growth and Increased Water Temperatures
Photosynthesis is a process that uses carbon dioxide, water, and sunlight to make oxygen and glucose. Most of the oxygen from the atmosphere comes from photosynthetic algae. Aquaponics water being exposed to direct sunlight allows for algae to grow. As photosynthesis in water occurs, it uses up the carbon dioxide naturally mixed in with the water from the atmosphere. This in turn decreases the concentration of carbon dioxide in the water. As discussed, a lower concentration of carbon dioxide in the water will favor calcium carbonate to precipitate.
Calcium buildup in fish tanks is not detrimental to the plants and fishes of your aquaponics system but is an indicator of problems with your pH and nutrient balance. Addressing pH and nutrient balance is important to avoid calcium buildup from starting. It is important to have proper maintenance for your aquaponics system as this will keep your nutrient balance and pH levels in good condition. Part of aquaponics maintenance is having a cleaning system in place.