Aquarium Tips, Custom Aquarium Design

Live Plants in Your Freshwater Aquarium

Since freshwater fish are generally less expensive than marine fish, you might consider spending some of your budget on live plants. Keeping live plants in your freshwater custom aquarium will require proper preparation.

Your aquarium filter is less important if your aquarium has live plants because the plants will do some of the filtering for you. In order for plants to thrive they need three major elements:

  • light,
  • fertilizer, and
  • carbon dioxide (CO2)

The lighting is important because plants need energy from light to create sugars, which they will use to grow. Aquarium light output is measured in degrees Kelvin (ºK). Most bulbs are between 4,500ºK and 20,000ºK. As the Kelvin rating moves from 4,500 to 20,000, the light output changes from a yellow color to a blue color.  At about 10,000ºK appears very white. The lower Kelvin bulbs are ideal for plant growth. It is common for people to use a mixture of 4,500ºK and 6,500ºK to provide the optimum growth spectrum for the plants, as well as a slightly whiter spectrum for a more appealing look.

Another concern is the wattage of the lighting. The wattage translates to energy and the plants will grow more quickly and colorfully if there is more power available. You should have 2-4 watts of light per gallon of aquarium volume for live plants to thrive. To address this issue you will be faced with a decision about the format of the lighting to be used.

Standard fluorescent is the least expensive but is the weakest format. Next are Power Compact (PC), T/5 and Very High Output (VHO) lighting. In my opinion, these three lighting formats will give you roughly the same result and only differ in heat output and mounting format. PC and T/5 lighting seem to be common due to their availability in prefabricated enclosures and the actual bulb sizes. The last option is Metal Halide lighting, which is extremely powerful but also expensive to purchase and operate. They also produce extreme heat and can easily overheat the aquarium. For this reason, Metal Halide lighting is not a popular choice for aquariums with live plants.

Once you have considered the proper lighting for your plants, you must also consider proper fertilization. Although the leaves of a plant take in light and use it to create sugars for energy, the roots also need to draw in nutrients from the gravel and a good fertilized substrate will provide those nutrients. If this issue is considered in the design stages of your aquarium project, you will save yourself considerable time and energy later. Liquid fertilizers can be added to the aquarium on a routine basis but if you setup the aquarium with a fertilized substrate you can avoid having to use several different liquids.

Plants need to breathe as well as animals, but they do it differently than animals do. First, plants breathe opposite compared to animals. Instead of taking in oxygen (O2) and producing CO2, they take in CO2 and produce O2 during the day and then the process reverses at night when there is no light. Second, plants cannot pull air into their bodies, since they do not have lungs. They can only absorb what is touching the physical structure of the plant. This means it is crucial to make sure there is enough dissolved CO2 in the water for your plants.

CO2 can be introduced into an aquarium in a number of ways. One way is to use a liquid supplement, but the most effective way is to use a CO2 regulator system. This type of system consists of a CO2 gas cylinder, a regulator valve, a diffuser to mix the CO2 with the water, and a pH controller to turn the system on or off depending on the pH level of the aquarium. The aquarium pH will lower as the CO2 level increases so it is wise to use a pH controller to monitor and shut off the CO2 system before the pH level gets too low.

Don’t forget about maintenance when it comes to keeping a freshwater aquarium with live plants. If you feel that upkeep of your tank is a daunting task, we provide scheduled aquarium maintenance services appropriate for your setup. Keeping things clean and fresh is essential to the health of your aquarium and the animals within it.