Best Nitrate Remover for Freshwater

We’re going to kick this off with a super quick science lesson.

Fish waste turns into ammonia. Beneficial bacteria converts ammonia into nitrite. Other beneficial bacteria then converts this nitrite into nitrate. 

Quickest science lesson ever. 

Anyway, too much nitrate in your fish tank can be harmful to your fish. More often than not a quick water change usually solves the problem. But sometimes this just isn’t enough.

While nitrate in the tank isn’t quite as harmful as ammonia or nitrite, if there’s too much build up of nitrate then the cumulative effect becomes toxic and can lead to nitrate poisoning and death. Similarly if introduced suddenly into high nitrate levels, the fish can go into nitrate shock.

Luckily, for those of you who’s tank frequently shows dangerous levels of nitrate there are products in the market which can really help. We’ve been checking them out, and we’ve handpicked the best of the best to show you, and our reviews on those are coming up very shortly.

We were careful to include both chemical treatments and nitrate reducing filter pads.

Following that, we’ve also got a handy buying guide for you which walks you through everything you might want to think about before you buy. Then we’re going to top that off with another handy section where we answer some of your most frequently asked questions.


This nitrate remover has been awarded the title of Amazon’s Choice for nitrate remover. Such a title is only given when a product is of a really good quality, and is also available at a fair and reasonable price.

The link should take you to the page where you can buy a whole 1 litre bottle, Which should be more than enough to bring your tank’s nitrate down to acceptable levels.

The exact dosage you need is right on the Amazon page. You need to use 5ml of formula for each litre of your tank’s capacity.

It’s important that you adhere to the manufacturer’s guidelines as best you can. This means that you apply the formula wherever possible to a canister filter, chemical filtration module or a box filter.

The product must be used consecutively over a number of days, until nitrate levels come down to less than 20 mg per litre. You will need to do a nitrate test every day to check the nitrate levels.

In addition to removing nitrate, this product can also remove excess ammonia and nitrites.

It’s highly recommended by customers, and has earned a 4 and half star average customer rating on Amazon.

We can confirm that this product is suitable for freshwater tanks.


  • Large bottle
  • Very affordable


  • Does not replace the need for water changes


Rather than having to regularly add chemical treatment to your fish tank, with this nitrate reducer pad placed in your fish tank’s filter, you can just leave the pad in place, and let it do its job.

It’s designed to allow water to pass through for filtration, and it’s fibers will trap unwanted floating debris, keeping your fish tank clear as crystal. And all without clogging. The basic idea is to remove solid organic compounds before they break down, and have the chance to increase the levels of ammonia and nitrate in your fish tank.

This nitrate reducer pad will efficiently trap both large and small particulates, and hence rapidly bring down nitrate levels and any toxic build up, reducing the risk of disease. This also has the added benefit of reducing stress in the fish too.

It’s quite big in size, 18 inches by 10 inches, but that won’t be a problem for you because you can simply cut it with a normal scissors to the right size for your particular filter. And you can combine it with any other type of pad that you use in your filter.

It’s thick and rigid design means it’s built to last. 


  • Less hassle than daily chemical treatments
  • Can be made to fit your particular filter


  • Doesn’t replace the need for water changes
  • The pad will also need to be replaced regularly depending on the nitrate levels in the tank


Now this treatment comes from a really great brand, and more than 50 years in the business they are truly well established.

Not only does this treatment remove excess nitrate from your fish tank but it also helps to remove ammonia and nitrite from the water too.

It’s super simple to use, there’s no measuring required. You simply add the contents of the pouch into your canister filtration system, and let it work its magic.

What really stands out to us about this treatment is that it’s completely re-usable, which makes it quite the money saver. And that’s simple to sort out too. You just place the granules into a salt solution and leave it to recharge. However, you must ensure that all of the salt solution has been removed from the granules before you place them in the filter for your freshwater fish.

It’s a good choice of nitrate reducer whether you’re starting your fish tank off from scratch or whether you have a more established tank if you’ve found dangerous levels of chemicals in there.

You will need to replace the Nitra-Zorb every so often, but just once every two months should do the trick.


  • No measuring required
  • Doesn’t require daily or even weekly renewal


  • Does not replace the need for regular water changes


What we love about this nitrate remove is that it doesn’t just remove nitrate, it’s also a water clarifier. It will clear the water whether it’s cloudy or whether it’s green from algae growth.

Adding ALGONE to the fish tank’s filter continuously removes the nitrate from the water in between water changes.

It’s safe to use for all freshwater fish, all bottom feeders, snails, plecos, frogs and live plants. And there are no known side effects.

Although we refer to it as a chemical style treatment, Algone is actually 100% natural, organic and chemical free.

You get 6 pouches in a pack. And all you have to do is place the contents of the pouch directly into the filtration system. And you only need to do this once a week, until you have achieved desired results.

Once you have achieved said desired results you can still continue to use the mixture every 2 to 4 weeks for preventative maintenance.


  • 100% natural, organic and chemical free.
  • Can also be used for preventative maintenance
  • No measuring required or tricky calculations to do


  • There are only 6 pouches in a box, but you can buy multiple boxes if necessary


Adding this filter pad into your filter, in addition to your regular filter, helps to create a dual filter system.

It’s designed to safely reduce both nitrate and nitrite levels in your fish tank. And it does this, as water flows through the filter, by trapping micro & macro organic particles, debris & excess fish food.

Reducing harmful levels of nitrate and nitrite in the water can really improve the well being of the tank’s fish. Not only does it reduce the risk of disease but it also reduces stress in the fish as well.

It comes in a big size, 18 inches by 10, that you can simply cut with a regular scissors to fit into your tank’s filter. The pad is extra thick too, which means it will collect more debris.

We can confirm that this product is suitable for freshwater tanks.


  • Less hassle than daily chemical treatments
  • Can be made to fit your particular filter


  • Does not replace the need for regular water changes

Best Nitrate Remover for Freshwater Buying Guide

As promised, here’s your buying guide which should help you ensure that you’ve thought of everything before you buy your nitrate remover for your freshwater fish tank.

Word of Caution 1

When you’re searching online for nitrate remover for your fish tank, a lot of the results that come up show treatments for salt water rather than for freshwater fish tanks. 

So, before you buy any particular treatment for your tank, first ensure that it is in fact for freshwater. You can rest assured however that all of the products in our top 5 picks are all suitable for use in freshwater tanks.

Word of Caution 2

Getting the perfect conditions in your fish tank can be quite the balancing act, and you need to watch out for a lot more than just nitrate levels. You also need to be mindful of other things, such as pH levels, and levels of other chemicals, such as phosphates. 

You should regularly carry out water checks, and ultimately, there is no treatment on the market that can adequately replace regular water changes. Every seasoned fish owner will tell you the same.

Remember you’re not always doing your fish a favor by overfeeding them, and this can in fact be a major contributor to excess nitrate levels in your fish tank.

Chemical Treatment vs Nitrate Remover Filter Pad

I guess the primary difference between going for a chemical treatment vs going for a nitrate remover filter pad is that using a special filter pad means less hassle and less fuss. 

You can put the nitrate filter pad in the filter and forget about it, whereas with a chemical treatment, the treatment plan usually involves putting the treatment in on a daily or weekly basis.

Also chemical treatments sometimes require an element of calculations to ensure that you don’t put too much of the chemical in for the particular size of your fish tank.

Other Features

Some nitrate remover treatments also work to reduce levels of other chemicals in the fish tank in addition to nitrate, such as ammonia and nitrite. In order to determine whether your particular tank needs such treatment, the best way to determine this is with a test.

You can get tests which test for several things at once, and we recommend that you invest in such tests, and carry out regular tests once a week, or more frequently if necessary.


A multi targeted approach is the best way to go. Check the water regularly, do regular water changes, use any additional pads such as nitrate reducing pads in your filter, and keep some chemical treatments on standby.

Although many fish owners will advise against chemical treatments in fish tanks, we would argue that if the fish need it, they need it.

Frequently Asked Questions

How do you lower nitrates in a freshwater tank?

For a quick summary of how to lower nitrates in your freshwater fish tank, please scroll up a little and refer to the conclusion of our buying guide.

What plants absorb the most nitrates?

We’ve done a little digging, and we’ve found that the freshwater plants that absorb the most nitrates are: hornwort, anacharis, duckweed, moss balls, and water sprite.

What filter removes nitrates?

It’s not so much the filter that does the job of removing excess nitrates in the fish tank, but more the filter pads inside. In our top 5 picks, we identified some really good nitrate reducing filter pads, specifically our number 2 pick, the EA Premium Nitrate Reducer Filter Pad, and our number 5 pick, the Professional Nitrate Remover Pad.

Regular filter pads are supposed to remove nitrates to some extent, but they just aren’t quite as efficient at doing so as the products we identified in our top 5 picks.

What should nitrate levels be in a freshwater tank?

The ideal level of nitrate for a freshwater is a maximum of 5 to 10 ppm (parts per million). This would be optimum. Levels of nitrate that go into 20 to 50 ppm are way too high. 

This sort of level could cause nitrate poisoning or nitrate and in the worst case scenario lead to your fish’s death.