How to Avoid Common Coral Issues

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How to Avoid Common Coral Issues

Nothing is more frustrating than looking at your beautiful reef tank and noticing your coral isn't as vivid and bright as it once was. Several common issues affect reef tank coral. Most of these problems can be prevented or controlled by simply maintaining a healthy tank environment through regular testing and maintenance.





Bleaching, as it sounds, is the loss of all color from coral. Many factors can lead to this problem, including high temperature, poor lighting, and imbalanced nutrient levels.



Coral can take on a brown color instead of its normal vivid coloration. As with bleaching, this can be caused by an imbalance in nutrient levels. Adverse lighting conditions may also be to blame in this situation.



This disease results in discolored patches of coral that can spread and lead to tissue loss. It can be caused by bacterial overgrowth, which can be controlled in a tank environment by monitoring nutrient and light levels.



If coral looks like it is losing tissue, it could either be experiencing Rapid Tissue Necrosis or Slow Tissue Necrosis. Both are extremely difficult to contain or stop. The best way to eliminate this problem is to consistently test and maintain tank parameters to prevent it from taking hold in your coral.




A healthy tank environment relies on the stabilization and maintenance of several key parameters. A change in any of these critical factors can significantly impact the others and the health of the coral.

  • Salinity
    • The amount of salt found in reef tank water can significantly impact the health of the coral. Levels too high or too low, or those that change drastically with improperly executed water changes and top-offs, can stress coral and even lead to death.
    • Salinity can be tested using a hydrometer which compares the density of the test water to that of pure water.
  • Temperature
    • A reef environment does not tolerate drastic temperature changes or an improper steady-state temperature. It is important to monitor temperature and take necessary steps to avoid temperature swings when adding or changing out tank water.
  • Alkalinity
    • Proper tank alkalinity is critical in maintaining pH levels as well as hardness. Coral can quickly lose beautiful colors if water hardness is not controlled carefully.
  • Nitrate/Phosphate
    • High nitrate and phosphate levels can create conditions for algae to bloom, making it difficult for coral to thrive. Cleaning a tank regularly can prevent these levels from getting out of control. Chemical additives are also available to control these levels.
  • Lighting
    • Tank lights too near or far from the coral can significantly impact photosynthesis and lead to bleaching and browning.


Regular monitoring, testing, and maintenance can make all the difference in avoiding coral issues that can be difficult to stop once they have begun. Please contact us with any questions! We would be glad to help you with any issues you may be experiencing.