What Planted Tank Fertilizer should I use?

Above: a colorful bouquet grown The 2Hr Way using APT 3.

Do we really need fertilizers for a planted aquarium?

If you want an ecosystem with thriving plants, the answer is yes.
If you are keeping only fish or specific livestock, probably no.

This is because aquatic plants require a full range of nutrients to thrive (unsurprisingly) and the aquarium ecosystem is incomplete. Fish waste and decaying matter can provide some nitrogen and phosphates, but woefully inadequate amounts of potassium, iron and other minerals. The use of soil (the real organic stuff) provides a source of food that can last for a few months, but is then depleted.

There is a tendency to compare our aquarium to 'nature', forgetting that the tiny world we have created is only a tiny selective slice of nature and is far from 'self-balancing'. And while we try to replicate nature, what we really want is a particular (and often unnatural) instance of nature. We want lush, thriving plants and a vibrant, algae-free animal population in crystal-clear water......crammed into a tiny, high-density space. Such environments do occur naturally in the wild, but often only at certain times of the year and under certain circumstances, whereas we want the same instance to be constant and never changing in our planted tank!

What fertilizer should I use?

It really depends on your objectives. While there are countless brands of fertiliser on the market, the concentrations and relative proportions of minerals in them vary greatly.

90% of popular off-the-shelf brands are designed for the casual aquarium hobbyist, where plants are mostly secondary.

Hobbyists looking to support a thriving planted ecosystem have generally had to combine a number of different fertilisers to achieve a better spread and concentration of nutrients to support richer colours and stronger growth. For the more serious planted aquarist, it is often a painstaking process of combining sometimes more than 10 different individual components (N, P, K, Iron, Magnesium and other trace elements) to achieve superior colour and form. The 2Hr Aquarist APT range of fertilisers is the result of this process and has been specifically designed to make this process faster, cheaper and less error prone by providing powerful all-in-one formulations with the right balance and concentration.

Above: a Tank using the Estimative Index approach, by Tom Barr

Many professional aquarists in the US gravitate towards the Estimative Index approach to providing nutrition, which is a methodology based on providing the tank with more than the maximum estimated nutrition that plants require. EI Style tanks are known for their colorful, nutrient-demanding plants. This heavy dosing approach comes with significant algae risk (due to the high levels of nitrates and phosphates) and requires a high level of plant husbandry skill to be used effectively. The APT Estimative Index formula makes it easy for aquarists to execute this dosing methodology through a simple all-in-one concentrate. Read more about the Estimative Index methodology here.

Above: a 'Nature Style' 2Hr Tank using APT 1 ("APT Zero")

In Asia in the 1990s, many serious aquarists followed the ADA approach, popularised by Takashi Amano. Unlike the Estimative Index approach, the ADA approach is super-lean, relying instead on a rich soil substrate (unlike Estimative Index tanks, which often use sand/inert substrates) to provide nutrients. ADA 'natural style' tanks grow more slowly and are known for their relative ease of maintenance and longevity. Importantly, they are predominantly 'green' with far less colour. APT 1was designed for aquarists to easily execute the ADA approaching to dosing, through an all-in-one formulation.

Above a 2Hr 'Farm Tank' using APT 3.

APT 3  came about because we wanted a middle ground. We wanted to grow the colourful, nutrient demanding plants found in Estimative Index style tanks, but with less algae and easier maintenance. ADA's extremely lean approach was too lean to support these plants, especially after the natural depletion of soil nutrients over a few months. 2Hr tanks are characterised by lush growth with splashes of colour and relatively easy maintenance.

What nutrients do plants need?

We cover this subject in detail in this article.