Feature Article
Planted aquariums. From keeping a clump of moss for spawning through to a breath-taking contest-winning layout,
successfully growing plants in our aquariums can be both a useful and beautiful thing to augment our fish-keeping
experience. Sadly, however, many hobbyists struggle to keep live plants. But like raising fish, raising plants can be simple to
do if you start with the hardier varieties and understand their basic care requirements. Additionally, with a keen eye and some
artistic flair, you can also create a stunning aquascape with nothing but basic plants when they are arranged and planted to
their best advantage around some well-placed hardscape.
In this article, I’d like to share my Top Ten beginner plants, as well as a few tips for using them to full advantage in an
aquascape. Once you have mastered the basics, continuing to learn about keeping aquatic plants and building your skill set in
creating lush aquascapes can be as addictive as learning about raising more difficult fish.
Overview and basic chemistry
Before we begin, let's review a handful of basic water chemistry which is critical for a successful simple planted tank. Firstly,
it is recommended to have a fully cycled (nitrogen cycle) tank with 0ppm ammonia and nitrite, nitrates under 40ppm.
However, plants have an affinity for ammonia over nitrate (though they will use both as a nutrient source), so a good load of
fast growing plants can actually help cycle your tank by removing some ammonia as well as seeding the tank with nitrifying
bacteria present on the plant itself. As you can see, healthy plant growth will remove both ammonia and some nitrate, leaving
your final nitrate level lower. It's also worth noting here that plants also absorb some metals and neutralise other nasties as
well as increasing oxygen, so they are excellent for aquarium health! Your pH should be between 6 – 8, though 6.5 – 7.5 will
usually yield better results. Temperature should be constant, and the usual tropical tank measuring between 22 – 28 C will be
ideal. Good lighting is crucial, and while this is a complex topic, for our purposes we can keep it simple. Try to ensure you
have a light which is strong in both the blue and red spectrums, with less green and yellow. Many manufacturers make bulbs
rated for plants, and these work very well. If you can't find this info, choose a bulb with a 'colour temperature' measured in
Kelvin (K) of over 5000K, and 'cool white'. Intensity is important too, and if you are using normal fluorescents (T8 or T5),
the 1.5 – 2 watt per 4-5L (or 1 gal) rule tends to work well. To achieve this, multiple bulbs over larger or deeper tanks are a
good idea. Compact fluorescents and LEDs are more efficient, so the watts per gallon rule fails here, but usually more
intensity is better than less. For tanks 40L (about 10 gal) or less, they are usually shallow enough not to worry too greatly
about intensity, and lights which are too bright may burn leaves, so stick with a normal bulb with the best plant colour you
can find.
Hardness is also an important factor, and comes in two types, general hardness (GH) and carbonate hardness (KH). Both are
measured in either parts per million (ppm), or 'degrees' (dGH or dKH), which equate to 17.9ppm for each degree. The first
kind, GH, is a measure of total dissolved mineral salts. These elements, predominately calcium and magnesium salts, are
important trace elements for both fish and plants, and are vital for their internal to external water/salt balance
(osmoregulation). Aim for a GH of 5 – 12dGH or ~50 – 215ppm depending on your chosen fish species. If your tap water
has a low GH, you can raise it by adding aquarium salts which are specially formulated to contain calcium, magnesium and
other trace elements. Never use regular salt (sodium chloride). The second type of hardness, KH, is a measure of dissolved
carbonates, or 'carbonate alkalinity'. This is not to be confused with water being alkaline, which is the same as being basic, or
having a pH over 7. Alkalinity is a measure of the 'buffering capacity' of water, being the waters ability to resist swings in pH
and keep the pH stable. Good buffering is very important in a planted aquarium, as the daily cycles of plants
photosynthesesis and nightly respiration can cause swings in the pH, which can be stressful or even fatal to fish. Essentially
this works by plants consuming dissolved CO2, usually in the form of carbonic acid, during photosynthesis during the day
and this can raise the pH (ie, make it more basic). At night, this stops and plants respire (ie, consume oxygen and produce
CO2) just like the other animals and bacteria in the aquarium. By doing this, more CO2 and thus carbonic acid is produced
and thus the pH is lowered again. Carbonates can absorb these changes well, and for good buffering, shoot for a KH of