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Above: an example of a Farm Tank managed the 2Hr WayTM, using APT 3/ Complete. Check out other tanks here


If you have a question regarding the use of APT fertilizers and are not able to find an answer here, please send us an email at (pictures really help) and we will get back to you as soon as we can (usually within 24hrs).

Which APT?

Which product is right for me?

which APT 



My goals

How fun! If you are keeping relatively few fish, use APT Complete. If you have a lively fish population, go for APT Zero. Without CO2 injection, plants have a far harder time outcompeting algae as their growth rates are limited by the low supply of CO2. We strongly recommend using a canister filter (it is worth the extra $) instead of a hang-on-back. The improved flow and larger bio-filtration capacity really helps to keep algae at bay. It is also far easier to support healthy plants using aquasoil instead of sand/ stone. 

Even with improved flow and a soil substrate, plant growth will be slow, which means your main task is maintain a stable environment over several weeks! This is the hardest part- patience. Most aquarists make the mistake of changing parameters every week, which disrupts healthy growth. Look out for new leaves. With APT's nutritional boost, new leaves should have better form and color. 

That is exciting! We always recommend proper cycling before adding plants and livestock- it does wonders to prevent algae from appearing in the first place. For optimal algae control, plants should go in ideally a month before you add fish. If you plan to keep softwater plants, always check your existing water parameters. While it is possible to 'push the limits', it is just so much harder. Read more about how to manage water parameters here. If you are using aquasoil and starting with a smaller plant mass, you can start with APT Zero before transiting to APT Complete after 3 months. This gives maximum algae control at the start, while providing sufficient nutrition for long term health thereafter.

For very mature tanks (>1 year old), it is far better to perform a reset than to try a partial reboot by adding a fancy new fert (even if it is ours) and adding new plants. A reset involves draining the tank, removing all existing plants and enriching / changing the substrate. While it is a major task, it gives more predictable results, especially if we use the reset as an opportunity to review (and improve) key infrastructure components. In a tank without CO2 injection, good flow and bio-filtration is paramount. We strongly recommend a canister filter. An aquasoil substrate makes a world of difference (but remember that soil depletes by 6 months). We recommend a full reset before replanting and adding APT.

In mature tanks with good infrastructure but merely lacking optimal nutrition, APT will make a clear difference. The improvement in a tank without CO2 injection will be observable only in a few weeks (things change slowly without CO2!) and the signs of improvement will be in the growth, form and coloration of new leaves. Old leaves do not recover. Unlike say human skin, plants are programmed to discard old leaves and channel their energy to growing new ones instead. So yellow, decaying and heavily algae-covered leaves should be trimmed away. They will not get better.

While APT is designed to reduce algae occurrence, it is not an algicide and will not by itself remove algae. It works by enabling plants to successfully outcompete algae, the same way that trees in a forest outcompete weeds for light and nutrients. It also smartly controls the amount of nutrients that trigger algae, while providing enough for healthy plant growth. We suggest reviewing the causes of algae, and the detailed guides on managing specific types of algae.


Certain minerals play critical roles in plant growth. Nitrogen for example is one of the central building blocks of plant proteins. Perhaps more importantly, plant growth is hugely tied to the most limiting available nutrient.

This is Justus von Liebig’s (1803-1873) famous Law of the Minimum. Our fertilisers work because Liebig’s Law lies in the heart of our proprietary Capstone Formula.
Painstakingly and perhaps uniquely comprehensive in nutrition, our fertilisers ensure that you no longer have to worry about ’nutrient deficiency’. APT Complete and EI are 100% comprehensive while APT Zero factors in the nitrates & phosphates already present in aquasoil and livestock waste.

Just as important as what plants need is how much they need. APT Complete was crafted based on the study of 2 of the industry’ most respected (and divergent) approaches- Tom Barr’s Estimative Index (EI) and Takashi Amano’s Nature-Style/ADA system. While EI focuses on providing nutrients in excess (and resetting through large weekly water changes), ADA focuses on quality growth at a more moderated pace.

APT Complete takes a middle path. It is a lot more concentrated than ADA to compensate for the ‘everyday / average / normal’ substrate used by most hobbyists, but less aggressive than EI. You get everything that EI offers- but just slightly more safely / slowly.

APT Zero allows you to enjoy all the benefits of the ADA approach- unparalleled algae control and the ability to unlock the richest reds in popular plants through nitrate limitation. It should be paired with the use of aquasoil and/or a higher fishload environment.

Each 5ml per 100L dose adds 3.8ppm Potassium (K), 1.8ppm Nitrogen (NO3), 0.7ppm Phosphorus (PO4), 0.05ppm Iron (Fe), 0.4ppm Magnesium (Mg) and additional amounts of Boron (B), Copper (Cu), Manganese (Mn), Molybdenum (Mo) and Zinc (Zn). 

The above dosage is designed to be dosed 4 times a week. So the total per week adds up to: 15.2ppm Potassium (K), 7.2ppm Nitrogen (NO3), 2.8ppm Phosphorus (PO4), 0.2ppm Iron (Fe), 1.6ppm Magnesium (Mg) and additional amounts of Boron (B), Copper (Cu), Manganese (Mn), Molybdenum (Mo) and Zinc (Zn). 

Each 5ml per 100L dose adds 3.8ppm Potassium (K), 0.05ppm Iron (Fe), 0.5ppm Magnesium (Mg) and additional amounts of Boron (B), Copper (Cu), Manganese (Mn), Molybdenum (Mo) and Zinc (Zn).

The above dosage is designed to be dosed 4 times a week. So the total per week adds up to: 15.2ppm Potassium (K), 0.2ppm Iron (Fe), 1.6ppm Magnesium (Mg) and additional amounts of Boron (B), Copper (Cu), Manganese (Mn), Molybdenum (Mo) and Zinc (Zn).

Each 5ml per 100L dose adds 5ppm Potassium (K), 4.6ppm Nitrogen (NO3), 1.5ppm Phosphorus (PO4), 0.16ppm Iron (Fe), 0.4ppm Magnesium and additional amounts of Boron (B), Copper (Cu), Manganese (Mn), Molybdenum (Mo) and Zinc (Zn).

The above dosage is designed to be dosed 3 times a week. So the total per week adds up to: 15ppm Potassium (K), 13.8ppm Nitrogen (NO3), 4.5ppm Phosphorus (PO4), 0.48ppm Iron (Fe), 1.2ppm Magnesium (Mg) and additional amounts of Boron (B), Copper (Cu), Manganese (Mn), Molybdenum (Mo) and Zinc (Zn). 

Yes, in tiny, chelated form.

But isn’t copper harmful?

The amount of copper in APT is so tiny that it is basically harmless. Copper can indeed kill- in the way that the electricity from a 120V AC socket can. But a 1.5V DC battery is quite different.

But isn’t it still copper?

The minuscule amount of copper in APT is in chelated (i.e chemically bonded) form that makes it digestible by plants, but harmless to livestock as it is in a different molecular structure. Chelated copper is also a common food supplement. Think of it as a 1.5V DC battery with an additional rubber casing.

Why have it at all?

Because in the correct structure and trace amounts, copper is both essential and beneficial to plant and livestock health.


By tank volume, we refer to the amount of water in a tank. Because a tank usually has hardscape and substrate, and may not filled to be brim, the tank volume is always smaller than the physical tank dimensions.

Dosage of APT is based on tank volume.

This said, absolute precision is less important than consistency. When in doubt, dose LESS, not more.

APT Complete should be the default choice. It provides the optimal balance of nutrition and algae control across a wide range of tank styles. It contains a complete set of nutrients necessary for plant growth and does not require additional supplementation.

APT Zero contains no nitrates and phosphates, and should be used if you have a fish population that produces adequate nitrates in the tank (specifically, If your tank measures >10ppm NO3 by end of the week with no fertilizer dosing and water change).

APT Zero can also be used to induce steep nitrate limitation in tanks, which gives the deepest reds in species such as Rotala rotundifolia and Ludwigia arcuata. This approach is usually paired with a rich substrate to prevent long term stunting due to low nitrogen levels. To this end, APT Zero can be used as a replacement for the ADA range of liquid fertilizers (Bright K neutral, Green brightly mineral and Green brightly iron) to similar effect.

Estimative Index would be your choice if you understand and seek to practice the EI approach to grow plants at a fast speed. EI has the highest risk of runaway algae issues if you have sub-par tank maintenance, sub-optimal CO2 levels or low plant mass. 

The default dosing rate for APT Complete/APT Zero is 5ml per 100L, 4 times a week. Alternatively you can dose 3ml per 100L every day. Both routines should be combined with a 30% water change every week. This dosing rate has been tested to work well for most tanks, however, if you have a very sparsely planted tank or a very densely planted one, you should adjust the dosage based on observations on plant growth. 

What about 3 times per week or even less frequently?

With APT Complete/ Zero, the 3ml per 100L per day equals approximately 20ml per 100L per week. You can divide that ~20ml per 100L per week across 3 days (7ml per 100L each time) or 2 days (10ml per 100L each time) or even just 20ml per 100L each week.

In general, plants do better with a more consistent level of nutrition. However hardy plants (Swords, Java Fern, Anubias, common Crypts...etc.) can generally accept more flux and still be OK.

In low light, slow-growth environments (<30 umols of PAR), sudden spikes in nutrition (if you dose only once or twice weekly) may still not invite algae problems if there is sufficient mass of hardy slow growers (vis a vis fishload).

But in general, dosing more times a week (consistently!) is better.

For EI, dose 5ml per 100L, 3 times a week. Alternatively you can dose 2ml per 100L daily.

EI routines should be combined with a 50% water change every week.

Yes. APT Complete, APT Zero and Estimate Index have been tested to be safe even for delicate strains like Crystal red/Caridina shrimps. Read more here.

The magnesium levels in APT are too low to affect your tank's GH levels.

APT provides ~1.6ppm of magnesium over the course of a week.
In comparison, 1dGH is around 17ppm calcium/magnesium ions.

So you would need to overdose APT by 10X to raise GH by 1dGH.

This depends on heavily on whether you have significant fish load in your tank.

Use APT Zero if you have persistently high NO3 levels (>10ppm) and use APT complete if your tank is densely planted with few fish.

If your plants were previously grown under the EI regime with its elevated nitrogen levels, a sudden drop to lean levels can cause stunting in some species. While most will recover in time (about 2-3 weeks); you can avoid this by gradually dropping nitrogen levels over a month rather than switch regimes immediately. Having a rich substrate (soils) as a backup also helps. 

While many brands of aquasoils like ADA aquasoil contain a high amount of nitrogen due to being enriched with ammonia, they may not contain optimal amount of other nutrients such as potassium or magnesium. Water soluble nutrients are quickly leeched off with water changes as well. Therefore, dosing should be done once there are plants in the tank. Having good access to the full spectrum of necessary nutrients allow plants to adapt faster in new tanks.

No, we do not use Glutaraldehyde in any of our fertilisers. Read more about the substance here.

The short answer is- Yes.
Purigen, activated carbon and other water polisher capture small particles that are invisible to the eye. We go into detail of what they capture in this article.
In normal use, the impact on APT is neglible.

Already using our fertilisers?

This largely depends on your light/CO2 levels as these are the main determinants of growth speed  in the tank. Go hereto revisit the 3 growth pillars of a planted tank.

If fast growing plants have been facing nutrient deficiencies, dosing APT produces dramatically quick effects within days - deeper reds, greener greens and new shoots should be well formed.

In slow growing low tech tanks, the impact can take several weeks, as the rate of change is very slow. The benefit of APT for slower growing non-CO2 tanks is that old growth lasts longer, and stays healthier. Healthier plants are more algae resistant.

Visit the gallery to view tanks of fellow aquarists using the APT / Capstone range of fertilisers. 

As a rule, old leaves do not rejuvenate, as plants channel their energy towards new growth.

This means that a yellowing leaf, or one already damaged with algae, will not become green again, no matter what you provide.

Look out instead for how the new leaves are doing: with good nutrition, they should be richer in color, be in better form and remain algae-free. For stem plants, you must replant the healthy new portions grown under APT, and discard the old stem and roots after the new portion has grown tall.

Slow growers such as Buceps, Anubias, Crypts and even Java fern often take months to show the benefits of improved nutrition. This is because of their naturally slow rates of growth.

In some cases, leaves may yellow after a month after planting because the plant is still adapting to the new tank environment, especially if the plant was grown emersed (only partially submerged) at the farm. This is natural. Look out for the newest leaves- if they are healthy, you are on the right track. The old leaves may not recover.

For a tank without CO2 injection, new leaves may take several weeks (even months) to form, as the rate of growth is very slow in such conditions.

The salts in all our fertilisers are stable compounds and can be exposed to air and room temperature without degradation. As a general rule, it is best to use the fertilisers within 36 months of opening.

Due to the concentration of the products, sedimentation / crystallisation is normal and may cause the contents to appear cloudy. In some (rare) cases, larger flakes / solids may be present. They do not affect the efficacy of the product and can be discarded.

While APT Complete and APT Zero are specially designed to reduce algae risk, many other factors affect the presence / absence of algae in a planted tank. This section identifies the different types of algae and the best ways to tackle them. Read this post for the best practices to having an algae-free tank. For a broader understanding of the science behind algae triggers, please go here.

If your plants were previously grown under the EI regime with its elevated nitrogen levels, a sudden drop to leaner levels can cause stunting in some species. It is natural and expected. Most plants will happily adjust to the leaner dosing envioronment in about 2-3 weeks.

You can avoid this by gradually dropping nitrogen levels over a month rather than switch regimes immediately. Having a rich substrate (soils) as a backup also helps.

While nutrition plays an important role, pigmentation is dependent on other factors as well. Light intensity and spectrum are both extremely important. Check out this post for more details. For picky species, CO2 levels have a big impact. Check out this section on how to improve your CO2 injection.

Yes; doing 30-40% once every 2 weeks will work as well. However, remember that the main aim of water changes is to reduce organic waste levels in the tank and to allow one to do siphoning of detritus, the aim is not the dilution of fertilizer levels - if you are facing algae issues, skipping this cleaning regime is probably not helpful.

If you regularly change more than 30% (say 40%, 50%....), you can still follow the recommended dosing regime. Consistency in dosing is far more important. For example, if you regularly change 50%...keep to that. Don't change 10% one week and 60% the next. Many aquarists do larger water changes because of higher fish load- that is a good approach.

For planted tanks with plants that favour slightly higher GH ranges (Rotala sunset, florida & Downoi), use APT Sky.

The iron content in the formula is more than sufficient. If you are thinking about iron from the point of trying to get plants more red - invest in a better light instead. Iron only helps to maintain pigmentation, dosing more beyond a certain level does nothing. Our 2Hr Tanks do not receive additional iron other than what is in APT complete. It would have been easy to make a fertilizer with much higher iron levels, but we have found that it creates more problems with no visible benefit. 

Unlike our skin, plant leaves do not heal. So the older leaves will not recover even if the nutrition is now optimal. The new leaves however should be in general larger and more vibrant. For most stem plants, wait for the new, stronger leaves to develop then consider topping and replanting that portion. 

If you are growing 'blood vomit' and other picky Eriocaulons, the primary cause of 'melting' is insufficient CO2. These are the some of the most CO2 hungry plants in the hobby and require CO2 levels in excess of 35ppm. 

With more optimal nutrition, the newer leaves tend to be larger and more vibrant. The older leaves last longer as well. In carpets, this can create a sense of unevenness- big fat new leaves mixed with sad-looking older ones. This is natural, as plant leaves, unlike our skin, do not heal. So the older leaves will never become similar to the new ones. 

The best way is to remove the old growth completely, and replant the new leaves, taking care to spread them out rather than planting them all together in a bunch. Most beginners plant in big clumps. Experienced aquarists plant in tiny, well-spaced out bunches to give room for the carpet to grow evenly. 


The name APT started as a short form for Advanced Planted Tank, which was the name of our original website. 

By default, our bottles do not come with pumps.
The 500ml and 1000ml bottles fit all standard "28/410" pumps.
"28-410" refers to the bottle's neck size.
You can use any off-the-shelf "28-140" pump and it would fit.

However, we are launching a bottle-with-pump version for all products soon- thank you for your understanding and patience!

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