How to Remove Phosphates for Fish Aquarium – A Beginners Guide

Knowing how to remove phosphates from a fish aquarium can be challenging for beginners especially since most aren’t aware that this compound is present in their aquarium.

Phosphorus is an element that is a byproduct of rotting organic matter. If you are an active gardener, you would know that it is commonly needed for healthy plant growth.

So, what role do phosphates have to play in an aquarium?

Phosphates are actually beneficial for the health of the fish. In fact, we all need a certain amount of phosphates as it aids in healthy cellular function.

However, as with all things, the key here lies in moderation. Too much of a good thing can be bad for you and your fish.

The same can be said about phosphates – when consumed in moderation, these are very beneficial for your fish tank.

However, if there is too much of this compound in the water, it can quickly start to cause harm. By understanding this, you can then further work out how to manage this component easily.

The Effects of Phosphate in an Aquarium

When there is too much phosphate, it can cling to the tank walls, décor pieces, and even leech into the soil. This can make the compound difficult to remove, even after the organic matter has been removed.

The good news is that most phosphate doesn’t harm fish in large amounts.

However, it encourages the growth of algae in the tank. Algae blooms are not only unsightly but drain a lot of oxygen from water. The low oxygen levels in the water can be disastrous for the fish.

Additionally, very few fish can survive in low oxygen waters so your fish might be weaker or start dying.

High phosphate levels can also mean that the algae bloom will be large and it can be difficult to remove.

Eliminating the algae bloom can be challenging at this point but not impossible. It will just take a lot of time and energy on your part.

The Common Sources of Phosphates

As previously mentioned, phosphates and phosphorus are naturally made when organic matter starts to rot. In an aquarium, this organic matter is introduced in different ways.

In fact, you might not even have noticed these things before.

The following are various ways that phosphates get introduced into a fish aquarium:

  • Leftover food – When fish don’t eat all the food, it starts to decay and rot which in turn, increases the level of phosphates in the water.
  • Fish Feces – All fish produce waste but if it isn’t removed, the waste will start to decay and you will have more phosphates.
  • Plant Decay – If you have live plants, they can take time to acclimate to the water but some can die and start to decay.
  • Dying Algae – When you treat your tank for algae, the dying algae can release phosphorus in the water.
  • Filter Media – Certain filter media, particularly the ones that include carbon, can introduce phosphates into the tank.
  • pH or kH Buffers – Sometimes, the buffers you use for the pH or the kH levels of the tank can also have significant amounts of phosphates.
  • The Water – Tap water can also contain phosphates naturally. If you don’t use water conditioners, you could unknowingly be adding phosphates to your tank.

Once you understand the sources of phosphates in your tank, you can then apply the appropriate measures in order to remove them from the water.

However, if you don’t know the source, you will have difficulties in properly getting rid of phosphates from your tank.

When you don’t know the source, everything hinges on guesswork.

It’s going to be a process of elimination until you discover the true source. Only then can you apply the appropriate measures to control it.

4 Simple Ways to Remove Phosphates from Fish Aquariums

Once you have identified the sources, you will have to rely on different methods to get the phosphates out of the water.

The following are some of the best ways that you can remove them from your fish tank without any worries:

Water Changes

Doing frequent water changes is a necessity but we’re not talking about the regular, weekly 10% to 20% change here. To remove phosphates, you will have to do large water changes that might even mean changing 25% to 30% of the water.

This process is necessary until you are able to properly address the main cause of the phosphate spike. Once you fix the issue, you can cut down on the water changes.

Remember that large water changes can be stressful for the fish because it messes with the nitrates, nitrates, ammonia, oxygen, and pH levels every time so be careful.

Deep Cleaning the Tank

It is a good idea to deep clean the tank when doing a water change and removing all the décor. Use a good algae scrubber to effectively remove any residue, even if you cannot see it as phosphates tend to cling to any surface area.

In fact, make it a habit to scrape the walls of the tank at least once a week.

Once the décor is removed, take a gravel vacuum and start cleaning the substrate to remove as much as waste, extra food, and other debris as possible.

This is a crucial step as fish waste can collect there and if you don’t have live plants, this waste will just accumulate and rot in the substrate.

Proper Cleaning of Décor

When you are cleaning the tank, don’t forget to clean out the décor as well.

You want to make sure that all unnecessary phosphate is removed. It’s a good idea to take a mild solution made with bleach and clean the décor pieces with it.

Soak them in the bleach solution and then soak them in water, keeping them submerged for 10 minutes.

Then, rinse the décor piece thoroughly before placing them back in the tank. Be very careful when rinsing to ensure that no bleach is left on the décor pieces.

Relying on Phosphate Absorbers

Sometimes, you can also get rid of phosphates in the water with the help of absorbers. These are specifically designed to absorb any amounts of phosphates that you have in the water. Keep in mind that they are extremely pricy.

This means that if the source of the phosphates is not determined, it can mean that you are using more of these unnecessarily. Nonetheless, if you are in a bind and need a quick fix, these absorbers will get the job done quickly.

Always follow all the directions given on the back of the bottle and don’t deviate from it. Overuse of absorbers can also have negative effects on the fish in the tank.

These are the simplest ways that you can remove phosphates from your fish aquarium. The good thing is that if you know the source of the phosphates, you can apply the appropriate measures without any difficulty.

Desirable Levels of Phosphates

Now, before you start scouring your tank to completely remove all phosphates, you should remember that a certain amount is needed. It will help to maintain healthy cellular function in your fish and any live plants. For this reason, you should not remove all the phosphates in your water.

However, you should be able to differentiate between healthy and unhealthy levels of phosphates. For this, you need to have a water testing kit with you. This kit can differ based on whether you have a freshwater or saltwater aquarium.

The ideal level should be 0.5 parts per million (ppm) of water. If the level is reading at 1.0 ppm, your tank is at risk of getting an algae outbreak. If it reads higher than that, you need to clean your tank and do a water change.

Unfortunately, water test kits only measure inorganic phosphates present in the aquarium. These are only a portion of the phosphate content in the water but it will mean that the organic content is equal to or more than this level.

As long as the phosphate levels stay steady at 0.5 ppm, your tank will flourish. Luckily, by the time the level starts rising, it will be time for a weekly water change so you don’t have to worry about it too much.

How to Keep the Phosphate Levels Low

To ensure that the phosphate levels in your tank don’t fluctuate too much, it is a good idea to use some good practices.

These will ensure that you avoid pushing the levels of phosphorus too high and have to resort to extreme measures to keep it away.

The following are some ways that you can keep phosphate levels low in your tank:

Check the Water Source

Using your water test kit, take a small sample of the tap water you are using and see how much phosphates it contains.

Most tap water can contain phosphates that give a reading of 1ppm but this is still a healthy level. If the reading is higher than 1, you will have to use a different water source for the aquarium water.

You might also have to use phosphate absorbers if you do not find an alternative water source.

Low Feeding

Overfeeding your fish can contribute to more fish waste in the tank. If you don’t clean up your tank on a weekly basis, the waste can then sink into the substrate and start to rot.

This means that it just leeches phosphates into the surroundings. This doesn’t mean that you should start to starve your fish. Just feed them plentifully but sparingly to ensure that they don’t produce too much waste.

Changing the Diet

It’s a good idea to consider switching the food brand you are using.

Flakes and pellets can be the biggest contributors to phosphate in an aquarium. Adding too much food also causes it to release phosphates while it is dissolving in the water.

Certain brands offer phosphate-free food pellets and fish flakes that you can use without worrying about changing the water parameters.

Frequent Water Changes

Make sure to always do weekly water changes as the phosphate levels can change significantly within a week. Never skip a week unless you are absolutely sure that your aquarium qualifies as a low maintenance one.

In such cases, you can get by without needing to change the water.

However, doing weekly 10% to 20% water changes will allow you to maintain healthy phosphate levels with ease.

Regular Tank Maintenance

Don’t skip on your tank maintenance duties, such as scraping the glass walls and vacuuming the substrate. In fact, you should make sure to do these on a weekly basis.

If fish waste has been absorbed into the substrate and needs to be vacuumed out, the gravel vacuum is one of the only ways that you can do this.

Regular maintenance contributes to keeping phosphate levels at a healthy and low level.

Don’t Overcrowd the Tank

When there are too many fish in the tank, they will also produce more waste and end up causing an increase in the phosphate levels.

Make sure that your tank is large enough to accommodate the fish type that you have.

Even keeping one fish per tank is more desirable than having a community tank where the fish are unhappy, stressed and dying.

Check the Filter

Always give your filter a cursory check to ensure that it is in good condition and does not have any debris in it. If debris is stuck in the filter, the filter could also contribute to increasing the phosphorus levels.

Additionally, check the filter medium you are using. If it is carbon-based, make sure that it has been treated beforehand to prevent the release of more phosphates into the water.

By paying attention to all these factors, you can maintain healthy phosphate levels and keep your fish happy and healthy for longer.

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