Sources of Phosphates in Marine Aquariums

Table of Contents

Phosphates (PO4) are a crucial parameter in marine aquariums that require constant monitoring and control. Excessive phosphate concentrations can lead to unwanted algae growth and negatively impact the health of corals. Understanding the sources of phosphates in the aquarium is key to effectively managing their levels.

Main Sources of Phosphates

  1. Fish Food: One of the primary sources of phosphates in marine aquariums is fish food. Both dry and frozen foods can contain significant amounts of phosphates, which are broken down by microorganisms after being introduced into the aquarium, releasing phosphates into the water.
  2. Fish Waste and Organic Debris: The digestion and metabolism processes of fish, along with the decomposition of organic debris such as dead algae and food remnants, also lead to the release of phosphates. Bacteria that break down organic matter convert it into phosphates, which then dissolve in the water. Therefore, if you have too many or too large fish relative to your aquarium’s filtration capacity, the phosphate levels will be too high.
  3. External Sources: Tap water used for top-offs and water changes can be another source of phosphates. Even reverse osmosis (RO/DI) water can contain trace amounts of phosphates if the filtration is not adequate. Phosphates can also come from the marine salt used to prepare the aquarium water.
  4. Rock and Substrate Materials: Certain types of rocks and substrates used in marine aquariums can release phosphates. Particularly problematic can be materials with high phosphate content, which may gradually release them into the water.
  5. Overdosing Supplements: overdosing supplements that raise phosphate levels in the water.

Other Sources of Phosphates in Marine Water

  1. Water Additives: It is also worth noting that some water additives, such as phytoplankton, amino acids, or chemicals, can contain phosphates.
  2. Unthawed Frozen Foods: If you decide to add unthawed frozen foods into the water, they will certainly increase the phosphate levels in the aquarium.

About the author

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Marek Protasewicz

Reefkeeping has been my passion for over 10 years now. I love learning. The hobby has taught me many valuable lessons, patience being the best example. Combining work and passion is my path. I run Crazy Coral, a marine aquarium shop, for a number of years. Building this business from the scratch I learnt from my own mistakes at a heavy cost.
Later I managed a project aimed at development of methods for quick growth of Corals in non-natural conditions. The project was carried out by Get Sales, Poland. Presently, I am responsible for distribution strategy at Reef Factory, of which I am a co-founder. The company produces smart devices for marine aquaristics. The last projects I have been involved in are Social Reef and ReefPedia.

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