Posts Tagged ‘Aquarium Articles’

Mono Potassium phosphate (KH2PO4) contains 22.8% phosphorous (P) and 28.7% potassium (K) It is used in planted aquariums and for hydroponic fertilisers Both phosphorous and potassium are macro nutrients.
It can be added directly to a planted aquarium but as phosphates are normally required in very small quantities it is easier to mix it with water (preferably RO or DI) to make a stock solution. It can also be blended with other nutrients to make a bespoke fertilizer.
If using the EI dosing system typical maximum weekly uptake figures might be:-
Phosphorous (P) 1ppm. Potassium (K) 30ppm

Aquarium Dry Dosing

Adding mono potassium phosphate at the rate of 0.0015grms per ltr to a tank will increase the phosphorous (P) level by 0.34ppm and the potassium (K) level by 0.43ppm.
Added 3 times per week levels will increase by:-
Phosphorous (P) 1 ppm
Potassium (K) 1.3 ppm

Aquarium Stock Solution

Adding 15g of mono potassium phosphate to 1 ltr of water will give a stock solution with the following analysis:-
0.77% P2O5 (0.34%P, 1.03% PO4)
0.51% K2O (0.42% K)
Added to the tank at the rate of 1ml / 10 ltr 3 x week will add 1ppm P and 1.3 ppm K.
You can shop online for mono potassium phosphate here

Potassium Nitrate (KNO3) contains 13.9% nitrogen (N) and 38.7% potassium (K) It is used as a source of Potassium and Nitrogen in planted aquariums, hydroponics and horticulture. Both nitrogen and potassium are macro nutrients – essential for healthy plant growth.

It can be added directly to a planted aquarium, or it can be mixed with water (preferably RO or DI) to make a stock solution. It can be mixed with other nutrients to make a bespoke fertilizer

If using the EI dosing system, typical maximum weekly uptake figures might be:-

Nitrogen (N) 4.5ppm. Potassium (K) 30ppm

Aquarium Dry Dosing

Adding potassium nitrate at the rate of 0.011 grams per ltr to a tank will increase the nitrogen (N) level by

1.5 ppm and the potassium (K) level by 4.3ppm.

Added 3 times per week levels will increase by:-

Nitrogen (N) 4.5ppm.

Potassium (K) 13ppm.

Aquarium Stock Solution

Adding 61g to 0.5 ltr of water will give a stock solution with the following analysis:-

1.5% N (6.7% NO3)

5.0% K2O (4.2% K)

Added to the tank at the rate of 1ml / 10 ltr 3 x week will add 4.5ppm N and 13 ppm K.

Shop here for Potassium Nitrate online

Fertilising a planted aquarium while eliminating algae

The Estimative Index (EI) was developed by Tom Barr and others. It is a method of ensuring that aquarium plants receive sufficient levels of nutrition without recourse to expensive testing kits and the like and with no danger of overdosing and harming the fish population.

Plants require certain nutrients and other elements in order to survive (See “Aquarium Plant Nutrition”)
Some of these nutrients might be provided by the fish population but some, if not all, will have to be added to the tank There are many proprietary fertilisers available which are specifically designed for use in an aquarium including products made by companies like Easy Life and SeaChem.
The big question however is “How much do my plants require?” The manufacturers do give recommended doses of course but the amount of nutrient required will depend on a number of factors including:-
Plant density, light intensity, growing conditions, and the availability of CO2 etc. Manufacturers will also ere on the side of caution and so plants may be lacking in certain nutrients. On the other hand excess fish food could be allowing phosphate levels to build up or nitrate levels could be rising from fish excrement.

Given these problems many aquarists resort to buying test kits which can be expensive and unless you spend a great deal of money are often unreliable.

The EI system is designed to ensure that plants receive an adequate supply of all the nutrients they require in order to thrive – without allowing an excessive build up of chemicals which could become harmful to both plants and fish.

It is based on two principles:-

1. Dosing quite large amounts of nutrient at regular intervals.
2. Regular and relatively large water changes.

The “Estimative” part of the EI system refers to the amount of nutrient required. The estimate is based on the maximum amount of nutrient that plants might need assuming that they are growing under ideal conditions – with maximum light and CO2 levels etc. In practise these ideal conditions will not occur and so the plants will have more than a sufficient quantity of nutrients.
This may sound alarming and you might assume that there will be a gradual build up to excessively high levels. In fact, as long as frequent and large water changes are carried out, the concentration of nutrients will level off. (See article on water changes)
Another cause for concern might be the potential cost of adding large amounts of nutrient only to discard some of the nutrients with the water change, but if the nutrients are added in the form of ‘dry salts’ which are very cheap when compared with the cost of some commercial fertilisers, then the EI dosing system is not at all expensive.
In fact the amount of dry salts required are quite tiny and it is often better to mix the salts with water to produce ‘stock solutions’

If you don’t want the bother of mixing up stock solutions that’s fine, Easy Life, for example, do produce all of the necessary nutrients – Nitrogen, Phosphorous, Potassium, Iron, Trace Elements and Carbon in their range of liquid concentrates

A major benefit of the EI system is that:-
When plants receive enough light, CO2 and nutrients,
not only will the plants thrive algae will not occur.

Water Changes

Regular water changes are important for the well being of any aquarium. Water changes remove dead and decaying matter from the tank and generally keep the level of what might be described as toxins to a minimum. Without any water changes the levels of these toxins would increase at a steady rate (until fish and plants start to die.) A 50% water change will reduce toxin levels by 50% and if these changes are done regularly (weekly) the amount that has built up over the previous week will be removed.
This will also apply to excess nutrients and although the EI system is based on dosing high levels of nutrients a 50% weekly water change will prevent any build up.

Dosing

It is impossible to say exactly what the nutritional requirements are but the following list is fairly typical of the maximum uptake of a well planted and well lit tank :-

Nitrogen (N) 4.5 ppm
Phosphorous (P) 1 ppm
Potassium (K) 30 ppm
Magnesium (Mg) 10 ppm
Iron (Fe) 0.5 ppm
Carbon dioxide (CO2) 30 ppm
Also required are trace elements.

Note these are weekly levels and would be added in smaller quantities say 3 or 4 times per week.

These nutrients can be found in a number of chemical salts, in particular:-
Potassium nitrate (KNO3)
Mono potassium phosphate (KH2PO4)
Potassium sulphate (K2SO4)
Magnesium sulphate (MgSO4)
Fluidsensor trace mix (Includes iron and other essential trace elements)
The other important requirement is CO2. This can be added as a gas but will require an expensive set up – regulator, needle valve, solenoid valve as well as a gas cylinder. A more convenient method is to use a product such as EasyCarbo which is manufactured by Easy Life and available from Fluisensoronline.

Typical Dose Routine:-
Potassium nitrate KNO3 0.011 gm / litre
Monopotassium phosphate KH2PO4 0.0015 gm / litre
Potassium sulphate K2SO4 0.011 gm /litre
Magnesium sulphate MgSO4 0.035 gm / litre
These should be added 3 times per week, every other day.
On the alternate days add Fluidsensor Trace Mix at the rate of 0.002 gm / litre
Every day add 0.02 – 0.04 ml / litre EasyCarbo

Sunday – 50% water change, add salts (or stock solutions) + EasyCarbo
Monday – Add trace mix + EasyCarbo
Tuesday – Add salts + EasyCarbo
Wednesday – Add trace + EasyCarbo
Thursday – Add salts + EasyCarbo
Friday – Add trace + EasyCarbo
Saturday – EasyCarbo

An important part of the EI system is that the amounts and dose routine are not cast in stone! If you miss a day or are away for the weekend it isn’t going to make any difference. Your plants will survive and your tank will come to no harm.

Stock Solutions

As the quantities of salts and trace mix are very small it is recommended that small amounts of the salts are mixed with water (preferably de-ionized or RO)

References:-
The Barr report
James Planted Tank
UKAPS.org

Just like animals plants need a source of fuel to provide energy in order to grow and thrive. The fuel source for animals is food – meat or vegetables which they eat. ‘Plant food’ is rather different in that plants ‘consume’ their food by absorbing simple chemical elements through their roots and leaves.

Plants contain chlorophyll which absorbs light. The light energy converts carbon, hydrogen and oxygen into sugars, starches and cellulose. These are called carbohydrates and this is how plants store the energy derived from light.
Oxygen (O), carbon (C), and hydrogen (H) are obtained from air (oxygen,) water (H2O) and carbon dioxide (CO2). CO2 is absorbed through the leaves of the plant and water through the roots. Perhaps surprisingly oxygen is also absorbed through the plants roots.

The process of using light energy to convert these elements into carbohydrates is called photosynthesis.

In addition to carbohydrates, plants require other essential elements – nitrogen for amino acids to make protein, magnesium is required to make chlorophyl and so on.

These essential elements can be divided into two groups:-

1) Macronutrients. These are nutrients required by plants in relatively large amounts. They are: nitrogen (N), phosphorous (P), potassium (K), magnesium (Mg), calcium (Ca) and sulphur (S)
2) Micronutrients. These are nutrients required by plants in relatively small amounts – sometimes referred to as trace elements. These include iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), boron (B), molybdenum (Mb) and chlorine (Cl)

In the natural world these elements can be found in the soil. However soils vary considerably in both their make up and consistency. Some may be rich in nutrients and others may contain little or no nutrient. Soils can be light and sandy. These soils may be well aerated but with little or no water retention. Some can be heavy or waterlogged, providing adequate water for a plant but restricting the amount of oxygen available. Over many thousands of years different plants have adapted to suit these different conditions.

In the artificial world the one thing we can’t do is wait for thousands of years for our plants to adapt to the conditions we provide. Whether it’s a plant in a pot on the windowsill or a container on the patio, a plant in an aquarium or a plant in a hydroponic system, it is essential that it is provided with the right nutrients and an adequate supply of water and oxygen at the roots, CO2 and of course light.

In any sort of contained planting, house plants, patio containers, planted aquariums or hydroponic systems, the most convenient way of ensuring that plants receive an adequate supply of nutrients is to use a specially formulated fertiliser. This may be in the form of powder, pellets or liquid but it is essential to use a product that has been designed for the application. You can’t use garden fertiliser in a hydroponic system and certainly not in a planted aquarium.

A maintenance programme is an important part of successful aquarium management and regular water changes are in important part of this routine. The big questions are ‘how much and how often’?

Filtration systems may help to reduce pollution in a tank but they will not solve all the problems. While a tank may look to be in good condition with clear water and healthy fish it could be the case that the fish are becoming acclimatised to a slow but steady rise in levels of toxicity. This is often the case when everything has been going smoothly for weeks on end and then suddenly everything starts to go wrong.

In all aquariums substances will be produced, which if left, become harmful – to fish and to plants.
These substances will appear from various sources. Dead or decaying plant materials produce toxins. Uneaten fish food will result in phosphates being produced and fish excrement will produce nitrates. Both of these elements are required by plants but there is no way of knowing how much there is. The fact is that if nothing is done, the level of toxicity will steadily increase.

The solution is to carry out water changes – where a percentage of the water in the tank is drained away and replaced with fresh water.

The following graphs show the effect of changing different amounts of water and at different time intervals. Without water changes the toxicity levels will increase indefinitely but do a regular water change and the toxicty will level off.
In order to keep toxicity to a minimum it is better to carry out large water changes on a regular basis. This is particularly important if you have a high fish population (or messy feeders).
If you follow the EI doseing system to feed your plants then it is important to change the water – 50% or more on a weekly basis.

An aquarium plant, like any other needs nutrients in order to survive. In the natural world – rivers, streams, ponds, fields and hedgerows, plants will find the nutrients that they need in the soils and sediments. Soils and sediments are not uniform, some may lack certain nutrients and some may contain other nutrients in abundance. Some plants can survive quite happily with low levels of some nutrients and for others to do well they may require high nutrient levels. This is one reason why you might find lots of plants of a particular species in one area and none in another

An aquarium however is not a natural world but a very artificial one! It is also finely balanced and has to be carefully managed in order to maintain conditions, which, as far as the fish and plants are concerned is as near natural as possible.
Water temperature, oxygen levels, pH and water hardness must all be controlled and just as fish need to have to have food, plants have to be given the correct nutrients in correct quantities.

In both agriculture and horticulture fertilisers can be provided from manure and composts. These are not options in the planted aquarium so chemical fertilisers are used. The main advantages of chemical fertilisers are that you know exactly what is being put into the aquarium and in what quantity.

Regular water changes are important in any aquarium to prevent the build up of toxins and as long as chemical fertilisers are used in conjunction with a regular water change routine, you will be able to control the conditions in the aquarium and maintain that fine balance.

The chemicals mainly used in planted aquariums are:-

Potassium nitrate – to provide nitrogen and some potassium
Monopotassium phosphate – to provide phosphorous
Potassium sulphate – to provide extra potassium
Magnesium sulphate – to provide magnesium

These provide the main macro-nutrients – nutrients required in relatively large amounts.

In addition to the macro-nutrients micro-nutrients are required – these are required in relatively small amounts. These can be sourced from separate chelates but as they are needed in such small amounts it is easier to use a ready made “trace mix.”

The information on the back of a bottle or packet of fertiliser can be difficult to understand. It may list the ingredients and  appear to give the % of each element, however things are not as simple as they may appear.

The three main elements in most fertilisers are nitrogen (N), Phosphorous (P) and Potassium (K). You may see three numbers prominently displayed on some fertilisers – 4 1 3 for example. This is the ‘NPK’ ratio and means (in theory) that it contains 4% nitrogen, 1% phosphorous, and 3% potassium.
However on the list of ingredients although you may find nitrogen (or N) you may not find ‘P’ or ‘K’. Instead you might see P2O5 and K2O (phosphorous pentoxide and potassium oxide) even though the fertiliser does not actually contain either of them!

It is done this way in order to comply with UK fertiliser laws.
The reasons are historical. In the 19th century and without the aid of the analytical instrumentation available today, the phosphorous and potassium content could not be measured directly. Instead the fertiliser was burnt and the residual ash, phosphorous pentoxide or potassium oxide, was measured instead.

There is another source of confusion to those of us who are not chemists! Many articles written about fertilisers refer to nitrate (NO3) and phosphate (PO4) rather than to the elements themselves. This is understandable because it is usually a nitrate that is providing the nitrogen and a phosphate that is providing the phosphorous. The good news is that it is easy to calculate the actual quantity of the individual elements and vice versa:-

From	To	Multiply By
NO3	N	0.226
N	NO3	4.427
P2O5	P	0.436
p	P205	2.291
PO4	P	0.326
P	PO4	3.066
K2O	K	0.833
K	K2O	1.2
CaO	Ca	0.715
Ca	CaO	1.399

If something contains 12% P2O5 it will contain 12 x 0.436 = 5.23% phosphorous

Other symbols and abbreviations often used in connection with fertilisers are %, ppm, W/V and V/V

% (per cent) is the same as parts per hundred. Potassium sulphate contains 44.9% potassium. This means that 100 grams of potassium sulphate contains 44.9 grams of potassium.
ppm is an abbreviation for parts per million. Some of the nutrients required by plants are needed in such small quantities that using % as a measure would have too many zero’s. 1 ppm = 0.0001%

Sometimes, after a % or ppm value ‘W/W’, ‘W/V’ or ‘V/V’ might appear. W stands for weight and V for volume. ‘W/W’ Means that the % or ppm has been calculated on a weight for weight basis.
In the example above 44.9% is actually 44.9% W/W i.e. weight per weight.

It is usual to measure solids (powders) by weight e.g. grams (g) or kilograms (kg) and liquids in litres (l) or mille-litres (ml).
When a solid is dissolved in water however it is often easier to calculate the % of an element or the ppm as W/V (Weight per Volume)