Designing a Planted Aquarium

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I have always had an interest in planted tanks along the lines of the Dutch and German set ups, but I have never had the space to try a similar set up myself. However a space has recently become available in the office. The main idea for the aquarium was to allow us to test some of the various equipment currently on the market. To this end all the equipment used is all readily available. The following sections will describe how the aquarium was set up and how I over came various problems.


Beautifully Planted AquariumAquarium
The size of the aquarium was limited by the available space, but had a total volume of 40 gallons and measured 36" x 16" x 18" deep. The extra depth allows the plants to achieve there full potential.


Filtration and Heating
In a planted aquarium effective biological filtration is essential but excessive turbulence and surface movement are to be avoided. Plants dislike growing in fast moving currents, but some movement is essential to avoid dead spots where debris can build up. Equally surface movement is to be avoided as this drives off carbon dioxide from the water and helps in the oxidization of essential minerals. For these reasons an eheim external power filte was chossen, the return from the filter was set below the water level to minimise turbulence and surface movement. The filter was packed with mechanical and biological media, initially no chemical media was used, as they are generally very un-specific in what they remove and would remove many essential as well as undesirable elements. A 150w Rena heater was used set to 78°F.


Because water is very good at absorbing light particularly in the red end of the spectrum (which is why deep water looks blue) high output tubes were used. In this case a 30" lifeglo with built in reflector, to the front and a 30" triton to the rear of the aquarium. In addition to enable the aquarium to be seen at night a 18" Blue moon was added. The two white lights are set for eight hours, and the blue tube is on constantly.



The chosen substrate was washed river sand which although difficult to locate is ideal because having a small grain size allows the roots to get a good hold, but is not so fine as to compact and stop root penetration. In addition it is inert and will therefore not affect water chemistry. A Rena heating cable was also used, this works by raising the temperature of the gravel by a few degrees, which stimulates water and nutrient movement around the roots as in nature. The heater cable was placed on the base of the aquarium and covered by a thin layer of river sand, over this was placed a thin (0.5cm deep) layer of laterite. This was covered to adepth of 6cm of river sand. The layer of laterite is essential as it provides good nourishment to the roots and therefore encourages a good root structure.


The water used was a mixture of 50% tapwater and 50% everse osmosis water. This dilution drops the pH to about 7, but more importantly removes enough of the buffering capacity to stop pH bounce when carbon dioxide injection is used. It is worth noting that what water to use depends on the chemistry of your local water. Our local water is very hard and alkaline with a high nitrate content, so a 50/50 mixture provides a good alternative without getting too involved in water chemistry.


All the liquid plant fertilizers we use are made by Aqua-Medic, because in our experience they provide the best results. Finally, and most importantly carbon dioxide injection is used, we use the Aqua Medic system, because it offers very controllable CO2 dosing, is reasonably priced, and the bottles are easily re-filled. CO2 is essential in a densely planted aquarium, because it is a lack of CO2 that is the primary limiting factor in photosynthesis and hence plant growth. Exact dosing is a matter of trial and error, if CO2 bubbles can be seen leaving the reactor then you are using too much. A good starting point is 1-2 bubbles per second, which in our system lowers the pH to 6.5 You can of course control the CO2 with a pH controller, which shuts off the gas when the pH reaches the desired point, but at the moment we are adjusting the gas manually as required.


Planting is very much down to individual taste, but the following should act as a guide. The most important point is to use true aquatic plants, which may sound obvious, but many plants available today are bog plants which will survive for up to several months submerged, but will ultimately die. As a general rule if you hold a plant upright by the roots and it stands up straight then it is more than likely a bog plant, if on the other hand the plant can not stand up on its own then it is likely to be a true aquatic plant. This is because aquatic plants do not need a supporting structure to stand up straight as they use the surrounding water. Remember that this is a general rule and there are exceptions. Secondly planted aquariums need time to become established and look there best. Too help speed up this process mix fast and slow growing plants, so that the aquarium achieves that matured look more quickly. Finally for inspiration look at the excellent Nature Aquarium book by Takash Amono.

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