Planted Aquarium Fertilizer Guide & (Dosing, Calculators, How-To & FAQ)

In this guide, you’ll learn how to use aquarium plant fertilizer for your planted tank.

Here’s a quick overview of what you’ll learn;

  • Types Of Planted Aquarium Fertilizers
  • How To Fertilize Aquarium Plants
  • When & How Often To Dose
  • Brief Overview Of Dosing Systems & Schedules
  • Where To Buy Your Fertilizer
  • And Much More…

We also decided to take a closer look at some of the best fertilizer for aquarium plants available. Of the many brands available, these are the best fertilizers you can use to for healthy aquarium plants in 2021:

  1. Best Liquid Fertilizer For Aquarium Plants2Hr Aquarist Ferts (Use Coupon Code: TFCG for 15% Off)
  2. Best Root TabsTropica Plant Care Root Tabs

Let’s begin.


Aquarium Plant Fertilizer

Most Common Types of Fertilizers for Planted Aquarium

The fertilizers you use for your aquarium plants aren’t the same as those you use for your garden plants.

There are various types of fertilizers that you can use to grow healthy aquarium plants.

Here are the main types you might use;

Liquid Fertilizers

Liquid fertilizer for your aquarium plants is just what you can assume by its name.

It’s a fertilizer in liquid form that is poured into the fish tank directly. It needs no prior preparation.

Liquid fertilizers are excellent for your aquarium plants because they are instantly available for the plants to use.

Liquid aquatic plant fertilizers are the best fertilizers for plants that absorb nutrients through their leaves rather than through roots.

They aren’t the best for heavy root feeders, though.

Dry/ Powder Fertilizers

Dry or powder fertilizers come in the form of pure chemical salts.

Unlike liquid fertilizers, they aren’t used as-is for your aquarium plants. They’re first dissolved in water and then introduced into the fish tank.

They’re salts that provide your aquarium plants the nutrients they need once dissolved.

Dry fertilizers are highly concentrated and shouldn’t be added to the fish tank directly.

They first need to be dissolved and diluted in water before added to the fish tank.

Root Tabs and Capsules

Root tabs and capsules are plant fertilizers compressed into tablet or capsule form.

These are relatively small in size and suitable for aquariums containing inert substrates like sand or gravel.

Root tabs and capsules aren’t added to the aquarium just like that.

Instead, these aquarium plant fertilizers are buried beneath the gravel in circles around the plant’s roots.

The tabs release the fertilizer slowly and gradually that the plant roots absorb.

Root tabs and capsules are most suited for heavy root feeds.

Natural Fertilizers

Natural fertilizers are fertilizers that are made from organic ingredients. They don’t contain any chemicals.

They’re extracted from the earth or living things and can be either animal-derived or plant-derived.

Some of the most commonly used natural aquatic plant fertilizers include eggshells, banana peels, and salts.

Click here to learn how to make aquarium plant fertilizer.

Aquarium Plant Fertilizer

What Fertilizer Should You Use For Each Plant?

Not all types of aquarium plant fertilizers can be used for all plants in your aquarium.

Different plants absorb nutrients through different routes; hence the type of fertilizer that will suit them varies.

There are two types of aquarium plants; root feeders and column feeders.

Root Feeders

These plants have robust, well-developed root systems. Although they absorb nutrients through their leaves, the absorption of a significant portion of nutrients is through roots.

These aquarium plants require a substrate rich in nutrients like gravel or sand with root tabs or capsules or aqua soil.

The aquarium plants that are root feeders and require root tabs for sufficient nutrition include;

  • Cryptocoryne
  • Vallisneria
  • Amazon Swords
  • Dwarf Sagittaria,
  • Red Tiger Lotus
  • Dwarf Hairgrass

Among many others.

Column Feeders Or Floating Plants

These plants absorb nutrients through their leaves. Their root systems aren’t as developed and extensive as root feeders.

The most common column feeder aquarium plants are;

  • Water lettuce
  • Red root floater
  • Duckweed
  • Several species of mosses
  • Hornwort.

The best type of fertilizers for aquarium plants that get their nutrients from the water column are liquid fertilizers that don’t usually settle in the substrate and are readily available to the plants for absorption.

Do You Need Fertilizer For Aquarium Plants

Yes, all plants will need some source of nutrition or plant food. The types above are the most common that you would use with a planted tank.

Soil alone typically won’t provide all the micro and macronutrients your plants will need to survive so be sure to always add some fertilizer to round out what your soil doesn’t provide.

How To Use Aquarium Fertilizers

The right way to use aquarium fertilizers depends on the type of fertilizer you’re using for your aquarium.

How you use a liquid fertilizer won’t be the same as how you use dry fertilizer.

So let’s explain how to use each type of fertilizer.

How To Use Liquid Fertilizer In An Aquarium?

Using liquid fertilizers in an aquarium is quite simple and straightforward. It’s as simple as adding food color to your beverage.

You pour in the appropriate dose directly into the aquarium, and you’re good to go.

Can Liquid Fertilizer Go Bad And Cause Cloudy Water In An Aquarium?

Liquid fertilizers are chemicals that usually go bad over time. However, their concentration may change due to evaporation.

One thing that makes liquid fertilizers an excellent option for your aquarium is that they don’t cause your aquarium to become cloudy.

The appearance of water in your fish tank stays unaffected.

How To Use Dry Fertilizers For Planted Aquariums?

Dry fertilizers require some extra work.

While you can add dry or powdered fertilizer directly into your fish tank, we won’t recommend this practice.

The fish may mistake the aquarium plant food for food and ingest the highly concentrated fertilizer particles.

The right way to use dry and powdered fertilizers is to dissolve it in water to dilute it and then pour it into your fish tank.

Or, you can add a bit of dry fertilizer underneath your substrate when you first set up your aquarium.

This will ensure that readily avaiable nutrients are ready to be used up by the roots of your plants.

How Long Does Dry Fertilizer Last In Your Aquarium?

Because you are diluting the dry fertilizers before you add them to your tank, they will be available to your plants until they are consumed.

If you’ve placed the dry fertilizers under your substrate, they will remain until the nutrients are depleted.

When that happens, you will notice deficiencies such as your plants turning yellow, which will let you know that you’ll need to add some root tabs.

How To Use Root Tabs & Capsules?

Root tabs and capsules aren’t water-soluble. You don’t just pop these tabs into your fish tank.

As you can tell by the name, these fertilizers are meant to provide nutrition to root feeders and aren’t meant to be left in the water column.

Root tabs and capsules are buried deep into the substrate, where they slowly release the nutrients that are absorbed rapidly through the root system of root feeders.

Ideally, it would be best if you kept root tabs every 4 to 6 cm throughout the substrate to ensure that all your root feeder aquarium plants receive optimum nutrition.

Aquarium Plant Fertilizer

When To Dose Fertilizer In An Aquarium & How Often

If you’ve got live plants in your aquarium, you’ll most definitely need fertilizers to ensure they get adequate nutrition.

The question is – how often do you need to dose fertilizers to your aquarium plants?

How Soon Should You Add Fertilizer For New Aquarium Plants?

When you add new aquarium plants, it takes them some days to adjust to the new environment.

During their initial days in your aquarium, their nutritional requirements are low as they’re trying to adjust and not grow.

However, when you first add plants to your aquarium, you should add small quantities of macronutrient fertilizer, one that contains potassium, magnesium, and calcium, from day one, so any nutrient gaps are covered.

As far as micronutrient fertilizers are concerned, like the ones containing iron, you should wait at least a week before you add them to your aquarium.

If the plants you’re adding are in their submersed forms, then it’s best to introduce micronutrient fertilizers to your aquarium from day one.

How to Dose Aquarium Fertilizer?

Dosing aquarium fertilizer predominantly depends on the size of your aquarium and the popularity of aquarium plants.

If your aquarium is small and only lightly populated, the dosing would be lighter as compared to an aquarium that’s heavily planted.

There are two popular dosing methods that you can use to dose aquarium fertilizer, namely EI (Estimative Index) and ADA.

The EI method involves using a high level of nutrients in the water column. In contrast, the ADA method uses a lesser quantity of nutrients in the water column but higher in substrates.

We will explain dosing systems in more detail below;

What Time To Dose Fertilizer In Your Aquarium?

There are several instances when there’s a need for you to dose aquarium fertilizer.

You should add fertilizer to your aquarium every time you change the water, add new plants, or when you start seeing visible signs of nutrient deficiency in your aquarium plants.

When you add live plants to your aquarium, they’ll need sufficient nutrition to thrive in a new environment, and adding fertilizers can transform the aquarium environment in their favor.

If you already have live plants, but you decide to add more, it should follow aquarium fertilizer dosing.

Moreover, if the nutrients are insufficient, they’ll start giving signs that will tell you it’s high time you dose aquarium fertilizer such as pale or white leaves, or the leaves will start withering away.

How Often To Dose Aquarium Fertilizer?

You can add fertilizer to an aquarium once or twice a week, depending on the size of your aquarium.

If your aquarium is large, you can use more quantity of fertilizer more frequently, whereas, for smaller aquariums, lower doses and lower frequency of dosing are sufficient.

You can overdose your aquarium with fertilizer, mainly because the plants in your aquarium will only consume a small amount each day.

So it’s best to spread out your dosing, in my opinion.

Video: Planted Tank Fertilizers Masterclass

If you’ve made it this far in the article luck you!

This video from Green Aqua is an awesome watch. These guys have some amazing planted tanks and they know what they are talking about.

It’s about 40 minutes but packed with so much information.

Overview of Dosing Systems, Schedules & Calculators

That said, there are many ways you can dose your aquarium fertilizer which we will explain below.

Types of Dosing Systems & Schedules

Estimative Index – EI Fertilizer Calculator

Aquarium fertilizer dosing through Estimate Index involves high fertilizer doses. It is designed to provide the aquarium plants a non-limiting environment.

This is based on the philosophy that when plants are well-fed, provided with sufficient nutrients, and they grow well. The dosing is such that the plants get more nutrients than what they need but in a balanced way so that the algae doesn’t get an opportunity to take advantage of excessive nutrients.

The EI method involves dosing all the nutrients in excess, followed by resetting the nutrient levels by significant water change where about 50% of aquarium water is replaced after a week. However, it’s only suitable for aquariums that are densely populated with aquarium plants.

The EI dosing method follows a 7-day long cycle. You need to add macronutrients to your aquarium on the first and micronutrient fertilizer on the second day to prevent any reactions between the two. You continue adding macronutrient and micronutrient fertilizers on alternate days for seven days.

On the 7th day of the cycle, you do a 50% water change that reset the nutrients levels, and you can re-start the dosing from the next day again that will mark the start of day 1 of the second cycle.

ADA Fertilizer Dosing Calculator

The Aqua Design Amano, or simply ADA, involves liquid fertilizers and ADA aqua soil, a nutrient-rich substrate for aquarium plants. The dosing of liquid fertilizers in the ADA method isn’t as aggressive as in the EI method. The substrate is the primary nutrient contributor here.

The ADA method of aquarium fertilizer dosing is a lot easier and straightforward than the EI method. It requires less hassle of maintaining the fertilizer to water ratio. Moreover, fewer nutrients in the water column mean a less favorable environment for unsightly green algae.

It’s far less sophisticated, making it more suitable for aquarists who are just beginning to set up their first aquariums and have little to no knowledge about water column fertilization.

Poor Man’s Dupla Drops – PMDD

The Poor Man’s Dupla Drops is a dosing method designed for fulfilling two purposes; to provide the plants with sufficient nutrition for healthy growth and prevent the development of algae. It limits the number of phosphates in the water that is what keeps the algae from growing.

The PMDD method of aquarium fertilizer dosing keeps phosphorus as a limiting factor. Following this dosing method, you provide excess carbon dioxide, light, nitrogen, potassium, and trace elements while keeping phosphorus-controlled amounts.

This ensures optimal growth of aquarium plants and ensures that the plants utilize all of the available phosphorus and leaves none for algae.

While following the PMDD method of fertilizer dosing, you’re required to change 20 to 25% water every week so that there is no saturation of any nutrient, which may impact your aquarium and its conditions adversely.

Perpetual Preservation System – PPS

The PPS dosing system can follow either of the two approaches; Classic and Pro.

The PPS Classic approach involves using five nutrient solutions whereby each is adjusted to meet the needs of the planted aquarium plants as closely as possible. The five solutions that are used in this system include:

  • Standard Solution (SS)
  • Phosphate Free Solution (PFS)
  • Nitrate Free Solution (NFS)
  • Magnesium Solution (MS)
  • Trace Element Solution (TE)

The PPS Pro approach uses only two nutrient solutions, making it easier to follow and achieve the desired results.

  • Macronutrients
  • Micronutrients

Aquarium Fertilizer Dosing Calculator

Regardless of which dosing method you use, you may want to know how exactly you can calculate the dose of aquarium fertilizer that you’re required to use.

For that purpose, you can use the dosing calculator by Rotala Butterfly that is still in its beta phase, or you can rely on dosing charts.

The doses are usually mentioned clearly on the fertilizer packaging, so you know exactly how much of the fertilizer product you’re required to add to the aquarium.

Aquarium Plant Fertilizer

Where to Buy Aquarium Fertilizer?

My favorite place to buy is from 2hr Aquarist and I believe they have the best all in one aquarium plant fertilizer check out this 2hr aquarist fertilizer review.

Aquarium fertilizers are readily available in your local shops. However, if you want us to list down some reliable places where you can buy aquarium fertilizer, below is the list for you:

  • Amazon
  • eBay
  • Petco
  • Aquarium Store Depot

Plant Aquarium Fertilizer FAQ

How to measure nitrate fertilizer levels in your aquarium?

It’s possible to measure the nitrate levels in your aquarium using the nitrate test kits.

These test kits contain different chemicals. You’re required to conduct a series of chemical tests to calculate the exact levels of nitrates in your aquarium.

The color of the final solution is matched with the chart to see the value it corresponds to.

Does aquarium fertilizer harm fish?

Aquarium fertilizers don’t usually harm fish, but aquarium fertilizers can harm your fish if you overdose on phosphorus and nitrogen.

How long after dechlorinating the aquarium can you add fertilizer?

It’s best to wait for at least a day before you can add fertilizer to your aquarium after dechlorinating.

This is because it gives ample time for the aquarium to filter out most of the chemicals from dechlorination.

Not doing so would only result in your fertilizer going to waste.

How long after a change of fertilizer will you see changes in aquarium plants?

The plants will start absorbing the fertilizer’s nutrients as soon as it’s made available to them. You will see changes in your aquarium plants after a few weeks, so be patient.

What should I do if I spill my fertilizer in the aquarium?

If you spill fertilizer in your aquarium, you should immediately change the water.

If the fertilizer contains too much phosphorus, it might harm your fish. Too many nutrients may also promote the growth of algae in your aquarium.

Do I need to turn my filter off when I add fertilizer to my aquarium?

No. Turning your filter off when you’re adding fertilizer to your aquarium isn’t necessary.

When your filter is on, it makes the fertilizer spread throughout the aquarium faster.

What is potash used for in aquarium fertilizer?

Potash or potassium sulfate is a vital element of a fertilizer that promotes the healthy and rapid growth of aquarium plants.

The more potassium in your aquarium, the faster your plants will grow.

Do I need to add fertilizer to my aquarium if I’m not using CO2?

Aquarium plants need both CO2 and nutrients (macronutrients and micronutrients) for optimal growth.

If you aren’t adding CO2 to your aquarium, your plants will utilize what’s available to them. However, you will still need to add fertilizer to your aquarium to ensure your aquarium plants’ optimal and healthy growth.

Aquarium Plant Fertilizer

Jack Dempsey
Follow Me