Plants are sensitive to subtle changes in the water. Not nearly as sensitive as fish but over a short period of time you will start to notice a change in them if you do not supply the right amount of light and nutrients. Light is by far the most important, for without light your plants would not grow. Nutrients is needed as plants use these to grow to their maximum potential.
By looking at the leaves of a plant closely you can get an indication about how the plant is doing in the aquarium. Sometimes it is hard to tell what nutrients maybe needed because certain signs of leaf decay can be linked to a few lacking nutrients. It is best to keep the aquarium dosed with enough of each nutrient so the plant can grow optimally.
In an aquarium full of different plants, there will be certain types growing better than others. Some plants will need more of one nutrient and less of another depending on their origin. Certain plants will need time to adjust to a new tank. Melting (deteriorating) leaves are an indicator of this. This is normal as the shock of changing environments puts stress on the plant. Over time these plants will grow accustom to their environment and start growing normally.
Each piece of information has to be taken into account to maximize the plants ability to grow. Nutrients are broken up into 2 groups mineral and non mineral. Mineral nutrients are macro and micro nutrients. Non mineral nutrients are Hydrogen, Oxygen and Carbon
Below is a list of the main nutrients that need adding in an aquarium;
Carbon – Required for photosynthesis, plays an important role in the growth rate and health of plants. Approximately 45% of a plants dry mass is CO2. It increases plant efficiency and allows the plant to grow at rapid rates. CO2 is present in very low doses under water and needs to be supplemented by gas or liquid. This is not needed for every aquarium, as plants will still grow without it, but to bring about lush, vibrant, accelerated growth then supplementation is necessary. CO2 levels of 15 – 30ppm is what to aim for.
Primary Marconutrients or Major Elements
These are consumed in large quantities and the most important of the elements required by plants. For nitrogen up take, most fish waste will supply enough ammonia which then will be finally converted to nitrate, all being consumed by your aquarium plants. Potassium can be found in minute quantities but not enough for plants to sustain required growth. This will have to be added – usually through a liquid, powder or substrate fertilizer. Phosphorus will also come from your fish waste and any uneaten food.
For heavily stocked or quick growing planted tanks, a nitrogen and/or phosphate supplement may need to be added if the ratio of plants far outweighs that of fish. Potassium Nitrate (KN03), Potassium Sulfate (K2S04) or Mono Potassium Phosphate (KH2P04) can be added as well as any liquid or substrate fertilizer with the required ingredient. This will help to give an adequate supply of primary macronutrients to the aquarium.
Nitrogen (N) – An essential part of the proteins in plant cells. Also a much needed part of chlorophyll, responsible for photosynthesis. This is extremely important for leaf growth, helping them with rapid growth. Nitrogen deficiency include stunted growth, with pale green or yellow leaves or slow growth. Aim for levels from 5 – 30ppm
Potassium (K) – Promotes chlorophyll production as well and helps in the strength of cells and the regulation of water through the plant. Also helping in the reduction of disease. Lack of potassium leads to weak stems. Leaves may wilt with yellow or brown tips or scorched areas. Aim for levels from 10 – 50ppm
Phosphorus (P) – Another essential part of the proteins in plant cells, important in growing tissue. It promotes development of seedlings, root growth and blooming. Lack of phosphorus causes stunted growth, discolouration of leaves and poor root growth. Phosphorus can cause algae blooms in the aquarium if too much is present. Aim for levels from 0.5 – 3ppm
Secondary Macronutrients or Secondary Elements
Secondary Macronutrients do not have to be added in as larger quantities as Primary Macronutrients but more is required than Micronutrients. Most of these will be present in tap water and depending on your area, certain water supplies will be harder than others. Some plants require a higher level of secondary macronutrients and an addition of these may need to be added to maximize growth. Calcium Sulfate (CaS04) and Magnesium Sulfate (MgS04) can be used in the required amounts.
Calcium (Ca) – Essential in the structure and strength of cell walls, helping the movement of other elements throughout the plant. Promotes proper functioning of growing tissue, especially in root tips. Infrequent water changes lower calcium levels. Lack of calcium leads to stunted root growth and stunted leaf growth on new leaves.
Sulfur (S) – Essential for many plant proteins. Helps in chlorophyll production. Promotes the development of vitamins and enzymes. If a lack of sulfur is present, plants cannot make full use of available nitrogen and other nutrients for maximum growth. Deficiency symptoms are yellowing of younger leaves then progressing to older leaves & stunted growth.
Magnesium (Mg) – Important part of the chlorophyll in green plants which is important in photosynthesis. Also a plant activator at helping enzymes needed for growth. Lack of Magnesium can cause leaf yellowing, especially on older leaves which will in turn lead to younger leaves.
Micronutrients or Trace Elements
Needed only in minute quantities and an excess of trace elements will be more damaging than helpful. They regulate growth and help produce chemical compounds in plant cells. These are added through liquid, powder, capsule or tablet form. The micronutrients listed below are the main ones that need adding to a planted tank. It is better to purchase a pre dosed amount than to add separately, risking an overdose.
Iron (Fe) – Not a part of the chlorophyll structure but small quantities are needed for its formation. Important in photosynthesis and also helping in the movement of oxygen around the plant. Lack of iron can result in yellowing or browning of younger leaves.
Manganese (Mn) – Needed to form proteins and necessary for photosynthesis. Helps increase the availability of calcium and phosphorus. Deficiency symptoms are yellowing of younger leaves, especially between the veins or discoloured spots on leaves.
Copper (Cu) – Important for photosynthesis and the activation enzymes. Important for growth reproduction. Lack of copper leads to leaf mottling and yellowing in younger leaves, weaker cell walls and lowering of proteins.
Zinc (Zn) – Also important in the activation of enzymes and the production of chlorophyll and carbohydrates. Lack of zinc leads to stunted growth, leaf mottling and yellowing in younger leaves.
Boron (B) – Important in growing tissue in young shoots and roots. It is involved in cell division and development. Aids in the production of sugar and carbohydrates. A deficiency leads to internal tissue damage and stunted bushy growth.
Molybdenum (Mo) – Helps with the conversion of nitrogen into plant protein. Important in the building of amino acids.
Types of Fertilizers
Substrate Fertilizer Adds nutrients directly into the root systems of the plant. This can come in soil, laterite, sand, tablet or capsule form. A lot of soils help at keeping the levels of pH low to maximize the plants ability to grow. Laterite is a layer that is placed under the top layer of the substrate where plant roots can benefit. Certain sands are enriched with nutrients for plant growth. Root tablets and capules are placed directly where needed next to plants roots.
Liquid Fertilizer Adding a liquid fertilizer to a tank is the eaisest way to feed your plants, usually daily or weekly. There are a lot of different fertilizers on the market ranging from potassium/iron supplements, individual supplements e.g. nitrogen, potassium or phosphours, mirconutrients and combinations of all of the above. At the very least use a potassium/iron fertilizer for your aquarium plants as this along with your fish & food waste will give them a majority of the essential nutrients they need.
Powdered Fertilizer These are chemicals in their rawest form and are by far the cheapest way of supplying nutrients to the aquarium. There are different combinations available and care needs to be taken to make sure not to overdose. Some examples are: Potassium Nitrate (KN03), Potassium Sulfate (K2S04), Mono Potassium Phosphate (KH2P04), Calcium Sulfate (CaS04), Calcium Nitrate (Ca{N03}2) Magnesium Sulfate (MgS04), Magnesium Nitrate (Mg{N03}2).
Always use test kits to make sure you have enough nutrients available for your plants and in turn the correct parameters for your fish. Throw out older test kits as these can give you inaccurate readings. Nutrients play an extremely important role in the growth of your plants. If your plants are not looking good then adding the above nutrients in required amounts will help you become more successful with plant growth. Plants grow themselves, we just have to set the right environment and give them the appropriate ingredients for this to come about. Once you become familiar with what’s needed, then it is easy to maintain a healthy planted aquarium.