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4 Important Tips for a Successful Aquascape - Part 2

4 Important Tips for a Successful Aquascape - Part 2

Dec 04, 2020

Cheng Hoo Sew

Video in Cantonese with Malay subtitle

So how do we actually utilize and control nutrients (aka fertilizer) in a planted aquarium and why is it important for a successful aquascaping aquarium? 

As stated in the first part of this tutorial, nutrients for plants are separated into 2 categories: MACRO and MICRO. Macronutrients are nutrients that are abundant in concentration, whereby they should be kept in a certain saturation all the time; while micronutrients are nutrients that are only found in very low concentration and do not need to be maintained at a certain saturation for a long period of time. 

Knowing this, it is obvious that all brands for aquatic plants’ nutrients have the same objective, that is to supply said macro and micronutrients. This in turn means that there is no major differences in the effectiveness of each brand, whereas knowing how to control and utilize the products have much more major influence on the success of your aquarium. 


When people talk about macronutrients in aquascaping, we usually refer to NPK which is nitrogen, phosphorus and potassium. But the truth is carbon (carbon dioxide) and GH (General Hardness caused by calcium & magnesium) are also part of the macronutrients required. We have already talked about carbon dioxide in the previous tutorial, therefore we will only focus on NPK and also touch a little bit on GH.

Aside from carbon, NPK definitely plays a very important role in a successful planted aquarium and it is also the cause of many failures due to the lack of understanding on these nutrients. This is because not only do these 3 nutrients need to be kept in a certain saturation in the water but also in a certain ratio from each other as well. On top of that, many brands of said nutrients are not very detailed on how to maintain this ratio and that makes it very confusing. 

In general NPK needs to be kept in the ratio of 5:1:20, which is when you have 1mg/L of phosphorus, you’ll need to have 5mg/L of nitrogen and 20mg/L of potassium. It looks pretty straightforward but it’s actually not. I will give examples of 3 different brands, Seachem Flourish, Continuum Aquatics, and Aquavitro to explain. 

Potassium, Calcium, And Magnesium

Starting with potassium, Seachem Flourish has a bottle of potassium and you’ll think you got it right if you follow the instruction of dosing it 2-3 times a week. But in the end you’ll most likely end up with a tank that is critically low in potassium. If you pay attention to the instruction, each dose only gives 2mg/L of potassium. Dosing them 3 times a week only adds up to 6mg/L. Remember we need at least 20mg/L. So what gives? 

You see, Seachem has another product that goes along with the Flourish Potassium which is the Equilibrium. It is labeled as a supplement for GH but actually contains potassium as well. If you follow the instruction of Equilibrium to raise the GH to 3dGH you’ll end up with 15mg/L of potassium. Adding that with the 2-3 doses of Flourish Potassium you’ll get the total of 19-21mg/L. 

They are doing this to provide more for their products to try to achieve better results with it. But because of the complexity, many users end up using it wrongly. You’ll see this pattern repeating itself later on too.

In contrast, the simple and traditional approach is used by brands such as Continuum Aquatics as their Flora VIV K will supply the total potassium that you need if you follow their EXPERT calculation. Multiply the volume of aquarium water in gallons with the mg/L of potassium that you wish to increase and multiply that with 0.083. For example, if you need to increase 20mg/L of potassium in a 15-gallon tank:

20 x 15 x 0.083 = 24.9

In other words, to increase 20mg/L of potassium in a standard 60p aquarium, you’ll need to add 5 caps of Continuum Aquatics Flora VIV K.

On the other hand, Aquavitro supplies their potassium in Aquavitro Carbonate KH which the name itself is even more confusing. To dose potassium which is a very important nutrient in a planted tank, you’ll need to buy a bottle named Carbonate. This can be confusing depending on where you get your aquascaping information from. In older practice, dosing KH into a planted aquarium is a must but recently it has mostly been deemed unnecessary. This is mostly because most plants do better in lower or zero degrees of KH. While some plants can utilize carbon within carbonate as their carbon supply but it is very ineffective.

Aquascapers used to dose KH to buffer the water so that water pH will remain mostly unchanged during and off CO2 injection. A value of 2-3dKH will achieve an ideal balance in between buffering pH and keeping the plants healthy. This is also why Aquavitro decided to place their potassium source in its Carbonate. The dosage of it will supply KH to about 2.8dKH and 20mg/L of potassium.

Potassium can be done weekly after water changes at a go. The amount to dose is usually dependant on the amount of new water that you’ve changed. This is the same for GH and KH. Which means compared to a more simple approach such as the Continuum Aquatics, you’ll pay around the same amount of money but will have to provide 2 things for your aquarium. That being said, using Seachem Equilibrium you’ll still need to dose 2-3 times of Seachem Flourish Potassium per week to achieve proper potassium value. But because of the complexity of it people usually end up not supplying the proper amount of potassium instead. If you use a potassium tester from time to time then you would not have any problems.


Speaking of testing, nitrogen sources can even be more confusing as though you don’t even understand the products completely, and testing the water for nitrogen will make things even worse. This is because many products use a simpler approach of supplying nitrogen in the form of nitrate. which means you can just test your aquarium nitrate level to determine the total amount of nitrogen. And this method is being widely taught too.

The problem is that some brands would use multiple sources of nitrogen. This is because plants perform better when there are multiple sources of nitrogen available. Seachem Flourish Nitrogen utilizes 2 types of nitrogen sources so you wouldn’t be able to get the most accurate nitrogen reading in your tank by just testing the nitrate. But you can roughly estimate the amount of nitrogen present with the test by doubling the result. For example if you have 2.5mg/L of nitrate when using Flourish Nitrogen, then there’s likely to be around 5mg/L of nitrogen. Aquavitro goes further on this as it utilizes 3 different sources of nitrogen, which means your tank should have almost 5mg/L of nitrogen if your nitrate test result is around 1.5mg/L.


Phosphorus on the other hand can be tested with phosphate testers no matter which brand you use. Do keep in mind that although by doing a simple Google search on NPK ratio, you normally end up with 5:1:20 or something within that value, but the actual phosphorus you need to keep your plants healthy is somewhere between 0.15-1mg/L. Most of the time your plants will do well between 0.15-0.3mg/L.

The ratio I would personally use is 1:0.15:20-30. I would not say that this is the best ratio but I’ve had no problems in all of my tanks with this ratio. Depending on the growth I would stay with 1mg/L of nitrogen and 0.15mg/L of phosphorus but double the saturation if I notice any stunted growth. Keeping the nitrogen low will be beneficial for red plants as I will explain later.



Nutrients that are present in a small amount are categorized as micronutrients. In aquascapes, this usually refers to iron and trace elements. While the concentration of iron in aquariums can be tested, trace elements cannot. 0.1mg/L of iron is normally supplied by most brands’ dosage and usually it can only be tested within 30mins after dosing as iron is rapidly absorbed by plants.

I usually would start dosing iron once a week and maintain it that way until I notice any iron deficiency whereby new leaves would appear yellowish. Do not confuse this with nitrogen deficiency in which older leaves appear yellowish instead of the new ones. Most brands for iron can be used up to 3 doses a week.

Dosing more iron to your tank will not make your red plants grow any redder. In order to have bright red plants you’ll need strong lighting and low nitrogen levels before adding more iron. Having proper lighting alone will cause the plants to grow faster. When plants are constantly growing fast, they will not waste time producing more pigments for their leaves as it is better to just grow more leaves instead. Therefore we will have to force the plants to grow slower by reducing the nitrogen and phosphorus. This will cause the plants to spend more resources in the colour of their leaves which in turn would need more iron.

Trace Elements

As for trace elements, it is rather simple even though there’s no testers available. That being said, each brand has their own ingredients for their trace elements. Aquavitro has a more advanced way of supplying trace nutrients for plants. Instead of containing minerals, Aquavitro Envy consists of carbohydrates, vitamins, amino acids, and polyunsaturated fatty acids and it is amazing!

On the contrary, Seachem Flourish Trace has a more traditional approach with its minerals based ingredients. But lately Seachem also introduced Seachem Flourish Advance which works great when used along with the rest of its Flourish line of products. Continuum Aquatics have its Flora VIV which supplies trace elements as well as small amounts of GH, NPK and iron which makes it also act as a single nutrient source for people who have a low tech tank.

Speaking of which, Seachem Flourish Comprehensive can be used for low tech planted tanks or planted tanks that mainly consist of slow-growing plants. It comes in two forms, liquid and tablet (aka Seachem Flourish Tabs). You should use only one and never both. Seachem Flourish Comprehensive or Tabs should also NEVER be used along with the rest of its Flourish product line which is for high tech tanks. One should also never mix brands as each brand has their own dosing system which might not go well with others. Unless you know exactly what you’re doing, you might end up killing all your plants.

Seachem Flourish Essential Starter Pack

My Personal Guideline

Now that everyone has a better understanding on macro and micronutrients, as a guideline, here are my own tips on how I usually balance the nutrients in my tanks. I usually use Aquavitro but this can be applied to other brands easily.

Upon starting the new tank, I would raise the potassium to 20mg/L and dose 10mg/L each time I do my weekly 50% water changes. This goes the same with GH. The rest of the nutrients will only be dosed in about 2-4 weeks later, depending on their condition.

Before adding nitrogen and phosphorus, I will do a nitrate and phosphate test first. All of the nutrients will start only once a week and the dose will increase depending on its condition and growth. Normally nitrogen and phosphorus will not be dosed more than twice a week, while iron and trace elements will not be more than 3 times a week. In fact most of the time I would just stick with 2 times a week or even once a week if I don’t see any symptoms of deficiency. 

For a tank that is 150L or larger, I will follow the instruction dose; whereas for a tank that is larger than 50L but smaller than 150L, I will only use 70% of the instructed dosage. And for a tank that is smaller than 50L I would only use 50% of the dosage. This is because smaller tanks have less water to hardscape and substrate ratio than larger tanks, and this means it has way less water than it should since the hardscape and substrate have already taken up most of the space.

This concludes the tutorial for having a successful aquascape aquarium. To recap, one must have the right water temperature before thinking about anything else as wrong temperatures will just kill the plants. Second of all, lighting should be taken seriously as without lighting plants can’t perform photosynthesis and without that process, plants can’t produce their food. CO2 is as important as lighting because plants convert CO2 to energy with light. Therefore, without proper light and CO2, plants won’t get any nutrients.

And if you’re wondering why I keep mentioning Aquavitro but their products can’t be found on our website, that’s because Aquavitro prohibits the sale of their products online. We can only sell them in our physical store but you can always PM us and see what we can do about that *wink*.