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Aquarium Setup

Aquarium Dark Start Method – the dark way to start your planted aquarium

Aquarium Dark Start Method – the dark way to start your planted aquarium

Aquascaping has a relatively new method to start a new aquarium called the Dark Start Method, also known as DSM. This method involves starting planted aquariums without lighting and in complete darkness without requiring extra water changes. This article will explain what it is all about and when it is advantageous to use the dark start method for your aquarium. 

Purpose Of The Aquarium Dark Start Method

The dark start method has only been in practice for a few years and is increasingly used in aquascaping. Aquascapers usually prefer very nutrient-rich soil, which releases a relatively large amount of nutrients into the water column, especially during the first few weeks of a freshly set-up aquarium. However, newly planted aquarium plants usually transition from emersed to submerged growth during the first few weeks. They do not consume a majority of these dissolved nutrients. Despite increased water changes, there may still be elevated nutrient concentrations in the aquarium, promoting algae growth. The dark start method can counteract a strong algae occurrence in the start-up phase.

Other Applications And Advantages

When using wood as a hardscape, an unsightly white slime often forms on its surface, better known as bacterial carpet. The bacteria form because the wood initially expels stored sugars, from which the harmless bacteria feed. Plants, e.g., such as Bucephalandras, that have been attached to the wood can react sensitively to the bacteria if they are in prolonged contact and can be damaged. Rama Twist Root wood, in particular, is known to have a very pronounced bacterial carpet, and a dark start is recommended for this type of wood.

aquarium hardscape

Suppose you want to keep the carpet-forming, grass-like, carnivorous marsh plant Utricularia Graminifolia (UG) in your aquarium. In that case, a dark start can serve you very well. The carnivore doesn't cope well with highly nutritious water - especially ammonia and nitrate - and often reacts with melting symptoms. For Iwagumi layouts incorporating UG with a nutrient-rich substrate such as active soil, a dark start is more than advisable. In case you want to plant only a little UG in the aquarium. Then you can simply introduce it a few weeks after the other plants at the preferred layout position. Namely when the content of dissolved soil nutrients in the water has decreased.

Utricularia Graminifolia

Maybe you have already used active soil as a substrate for past projects. In that case, you may know that it is advisable to perform more water changes in the start-up phase of the aquarium, e.g., 50% every other day during the first week. With a dark start, we don't need to introduce a water change for its total duration. Why? Because there is hardly any risk of algae growth. Algae also need light for their development, so it doesn't matter how much dissolved nutrients are in the water. As long as the component light is missing, algae can't grow. Again, other organisms profit from the free nutrients in the water column, which leads to the next benefit.

It consists of the fact that during the dark start period, the valuable bacteria strains in the filter and the aquarium can form without any risk to fish and invertebrates. In the process, the excess nutrients (especially ammonia) are flushed out of the soil and metabolized by the bacteria, i.e., simply eaten up. Thus, the nitrogen cycle can unfold, and you can relax and look forward to the stocking of the aquarium.

aquarium dark start method

How Does The Dark Start Work?

Like a conventional start, the aquarium is equipped with hardscape and substrate as desired, filled with water, and the filter circuit is started. Then you ideally add a bacterial starter product, and off you go on your relaxed journey. The difference to the conventional start is that there is a minimum of 4-6 weeks that the aquarium runs without lighting, CO2 addition, liquid fertilizer, or plants, and watch out without livestock.

aquarium dark start method

Usually, you can do little during this time. If running an open-top aquarium, you will probably have to add water occasionally due to evaporation. An additional measure should be taken for aquariums that receive a considerable amount of indirect lighting, e.g., from an opposing light source. The glass panes should be darkened with suitable material - any exposure to light is a risk and, in the worst case, could cause an algae explosion.

The Dark Start Is Completed - And Now?

Now you can drain the water down to the bottom of the aquarium and then plant your aquarium. Since planting an aquarium can take quite a while, it is recommended to keep the filter running. The filter should never be switched off for longer than 45 min. -  max. 60 min. Otherwise, the essential bacteria can die due to a lack of oxygen. Simply take a clean container (free of chemicals, not the cleaning bucket!) and fill it with aquarium water while draining. Then put the filter inlet and outlet in the container and continue running the filter this way. When you are done planting, and the aquarium is filled with water again, simply reconnect the filter to the aquarium.

After you switch on the light or set the timer, the CO2 fertilization (if available) should also be connected. Finally, you can be happy that some light comes into the darkness of your aquarium from now on.

Before introducing the livestock to your planted aquarium, the water values must be checked: Neither ammonium (NH4/NH3) nor nitrite (NO2) should be measurable. A bacteria starter product definitely helps to get positive water test results, and nothing should stand in the way of the livestock moving in.


There is no real disadvantage that we can report. If any, then there is only one noteworthy circumstance to mention. When practicing the Dark Start method, we should be mentally prepared so that we don't have visual benefits during this time. It is pretty dark, and apart from a bacterial lawn on wood decoration, probably nothing visible will happen. So, all you need is patience.

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