Aquarium Maintenance: How to Keep your Nitrate and Phosphate Levels Down

Are you unsure about the chemical well being of your aquarium water? Are you battling with high levels of nitrate or phosphates in your aquarium? If you’re having issues with build-ups, or if you’re not sure how to prevent them from escalating to begin with, then you’re in the right place. In our blog, we want to share our top tips for controlling nitrate levels in your tank, so your fish can have a healthy environment to thrive in.

What Are Nitrates and Phosphates Where Do They Come From?

First things first, you’ll need to understand what nitrates are to understand how to get rid of them. Ammonia is the harmful chemical that the waste in your aquarium creates. Nitrates (NO3) are produced when the bacteria in your filter breaks down this ammonia. Both nitrates and ammonia can be harmful to your fish, so it’s important to keep track of them and the effects they’re having on your aquarium water.

Phosphates can also create a harmful environment for your fish. Phosphates are the natural product of waste breakdown, including uneaten food, decaying plants and fish excrement. If you allow phosphates to build up in your tank, they can contribute to algae blooms, which can starve the water of oxygen, resulting in a poor environment for your fish.

Test Your Aquarium Water

Before you can begin tackling nitrates and phosphates, you need to know your water’s current nitrate levels. This will help you figure out how much action you need to take and how serious your build-up is. You can use nitrate and phosphate aquarium test kits to determine the levels in your tank. Some kits use colour dyes or strips to indicate levels in your tank, and some give readings in milligrams per litre (mg/l).

It’s important for you to know that nitrates are harmful when over 50mg/l, if your water reading shows your aquarium water levels are close to this, or even exceeding, then it’s time to start looking at how best to reduce or control nitrate levels. Phosphates should not be allowed to exceed 1mg/l. 

Reducing and Preventing Nitrate and Phosphate Build-Up

Now you know the chemical levels of your tank, it’s time to take the  following steps to reduce or prevent build-ups:

Water Changes

Sudden and drastic changes to your water chemistry can be just as harmful to your fish as the substances you’re trying to reduce, so you need to keep any changes gradual. If you’ve detected very high levels of nitrates or phosphates in your water, then it’s advisable to start by doing a 25% water change, which you can do easily with a jug or gravel vac. Repeat the process daily and keep testing the water until you’ve achieved a safe level.

Following this, if your chemical levels are acceptable, you should still maintain a regular water changing schedule and continue changing 15-20% of the water once a week. This will help keep your water free of many common harmful substances and provide your fish with healthy water to live in.

Avoid Overfeeding

Overfeeding your fish leads to a build-up of uneaten food, which decays and produces chemicals that can affect the overall wellbeing of your tank. This, in turn, can lead to harmful algae blooms, green water and other problems you want to avoid.

Keep a close eye on your fish when feeding and take note of how much they eat, making sure to only feed the amount they will eat within 2-3 minutes; this will allow you to determine how much they actually need, helping you reduce waste. You can also take a look at our blog How Much and How Often Should You Feed Your Fish and follow our advice to ensure you don’t let overfeeding cause unnecessary problems in your tank.

Don’t Overstock Your Tank

Fish produce their own waste, so it makes sense that having more fish in an aquarium generates higher levels of faeces, which in turn leads to higher nitrate and phosphate levels. The general rule is to allow one gallon of water for every one inch of fish, though this is only a rough guide and should be something you need to research before you set up your tank.

 If you think you might have too many fish in your aquarium, consider upgrading to a bigger tank to accommodate them and their waste levels – this will improve the wellbeing of the tank’s population.

Nitrate and Phosphate Absorbing Filter Media

Nitrate absorbing filter media can be added to practically any aquarium filter to help reduce levels in the water. Make sure you carefully read the accompanying information and instructions before trying a new filter media, following the instructions carefully.

You also need to ensure your filter media is regularly changed, otherwise the substances you’re trying to remove will simply be returned to the water when the media is used up, and your efforts will have been wasted.

Keep Live Plants or Live Rock

Planted tanks are the most natural way to keep nitrate levels low, as plants utilise a great deal of the ammonia and nitrites in the water to survive, this means less harmful chemicals living in the water. 

Live rock and sand also contain microorganisms that feed on the nitrates, preventing them from building up. Keep in mind, however, that heavily planted tanks perform best when only lightly stocked with fish, so this might not be the best option for everyone.

Additives & Treatments

If none of the above seems  to be making a big enough difference to the high levels of nitrate in your aquarium, you can try adding chemical additives and water treatments, which are specially formulated to tackle these substances. Many of the top aquatic brands like Seachem and Tetra offer additives that tackle algae, detoxify ammonia and nitrites and remove nitrates from the water. Ideally, however, chemical treatments should be used as a last resort, and not used as your go-to method for tackling these substances in the long term.

There are many means of reducing and controlling the nitrate levels in your tank, keeping your fish safe and creating a healthy environment for them to survive. Following our tips along with regular maintenance and water testing should help keep your tank and its water in the best shape possible. If you are still struggling with nitrate levels in your aquarium and want to know more about the safe use of additives and other preventative measures, give our team of experts a call on 01642 612419.

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