Table of Contents
Material / Tank
Capacity of a tank (Liters) = Length (cm) * Width (cm) * Height (cm) / 1000
Volume of the soil (Kg): Width (cm) x Length (cm) x Height (from the ground, from 10 to 15 cm) / 1000
Real water volume = Volume of the aquarium – Volume of the soil – Volume of the decorations (to be evaluated β¦)
Number of plants (estimate for a well planted tank ) = (L x W ) / 50
Maximum number of large fish (in cm of adult size fish) = Volume (Liters) / 2
Total weight = Estimation of the weight of the aquarium, water, decorations, gallery and equipment.
The minimum power of the water heater is given by the formula:
Water heater
P = 2 * F * A * dt
P = minimum power required in watts (it is prudent to add 50% to 100% to this value);
A = total area of ββthe panes with heat loss in dm2 (the bottom and the water surface are neglected, unless the aquarium is open);
F = thermal insulation factor: from 0.03 (good insulation) to 0.06 (poor insulation);
dt = Difference in temp. in degrees between the lowest room temperature and the desired aquarium temperature.
Number of fish in an aquarium – how many fish in an gallon tank
The indications are given here relate to the size of adult fish and not the size at the time of purchase. In fact, most of the fish sold in pet stores are juveniles and sometimes their adult size (from a few months to a few years later) is not commensurate with the size at the time of purchase. It is therefore advisable to inquire before any purchase! The classic rule is 1 cm of adultsized fish for 1 to 2 liters of water (depending on the size of the fish).
Fish size (cm)  Conservative values  Max valuesΒ container> 120L  Max valuesΒ container> 200L 
<5  1 fish for 5 L  1 fish for 4 L  1 fish for 4 L 
5 to 8  1 fish for 7 to 8 L  1 fish for 7 L  1 fish for 7 L 
8 to 10  1 fish for 10 to 20L  1 fish for 10 L  1 fish for 9 L 
10 to 15  1 fish for 30 L  1 fish for 30 L  1 fish for 28 L 
Aquarium Light
Electric power per real liter: from 1/2 to 1/3 W / L Light power per real liter: from 20 to 35 Lumens / L Efficiency of a good tube: from 40 L / W (for 15W tubes) to 65 L / W (for 58W tubes)
Aquarium PH
The pH value indicates the degree of acidity or alkalinity of the water. Acidity is due to hydrogen ions (H +), alkalinity is due to hydroxide ions (OH). The neutrality of the pH corresponds to a balance between these two ions and gives a value of 7 at the pH. A value less than 7 indicates acidic water, a value greater than 7 indicates alkaline water.
The pH is an important characteristic of water since each fish requires a particular pH. Bringing a fish to life in water of unsuitable pH causes weakening of the latter which will more easily catch all kinds of diseases.
H + ion concentration = 10 pH grams.
Hardness (total): TH (France) or GH (Germany)
In France the Total hardness is expressed in degrees TH, which corresponds to 10 mg / l of calcium carbonate (CaCO3). In Germany the total hardness is expressed in degrees dGH, which corresponds to 10 mg / l of Calcium Oxide (Quicklime, CaO). The carbonate hardness (also called temporary hardness) measures the Carbonates and Bicarbonates of Calcium and Magnesium, it disappears during boiling. Permanent Hardness measures Calcium and Magnesium Sulphates and Chlorides, it remains after boiling. In aquarium keeping, when we speak of hardness without specifying, it is Total hardness. We have the following relations:
Β° dGH = Β° TH / 1.7857 (total hardness in Germany) Β° TH = Β° dGH * 1.7857 (total hardness in France) 1 Β° = 1.43 Β° TH = 0.8 Β° dGH (total hardness in England) 1 ppm = 0.1 Β° TH = 0.056 Β° dGH (total hardness in USA)
Carbonate hardness: TAC (France) or KH (Germany)
The carbonate hardness indicates the buffering capacity of the water, it is a value indicating the stability of the pH: the higher the buffering capacity, the more the pH will be stable, while a low value will facilitate sudden variations in the pH of the water. water (harmful to fish). In France, Buffer Power is expressed in TAC degrees, which corresponds to 10 mg / l of calcium bicabonates. In Germany, Buffer Capacity is expressed in degrees dKH. The following table summarizes the relationship between these two measures:
CO2: Relationship between pH and KH
For a temperature of 15 Β° C, the CO2 rate is given by the formula:% CO2 = 3.0 * dKH * 10 (7.00 – pH) In the following table: CO2 values ββthat are too high are in pink, perfect values ββare in green, too low values ββare in blue.
For temperatures over 15 Β° C (as is often the case in aquariums), the formula remains valid with negligible error.
It seems that inaccuracies in the pH or KH value are more detrimental to the accuracy of this formula. But the precision should be sufficient to be comparable to the precision of commercial CO2 tests.
On the other hand, the formula is only valid if the buffering power of the water is due only to CO2 or to bicarbonates/carbonates (no addition of pH or pH + or peat products, etc.). In the case of an addition of remineralizer or too much phosphate, the formula is no longer valid.
Size of CO2 cylinders and their duration
Depending on the size of the bottles and that of your container, the duration of the diffusion between two refills is variable. The following small table gives you some ideas of duration according to these two parameters.
Mixture between two waters of different hardness
If you want to increase or decrease the hardness of tap water by cutting it with water of different hardness, you will find here the formulas giving you the necessary volumes of each water.
Let us denote by DER the value of the hardness of the tap water, DED the desired hardness and DEO the hardness of the mixing water (reverse osmosis water, spring water, distilled water, rain water β¦) and V the volume of water (DED hardness) that we need.
The hardnesses are expressed in Β° TH, the volumes in liters. The formulas are as follows:
Mixing water volume (DEO hardness) = V1 = (V * (DER – DED)) / (DER – DEO) Tap water volume (DER hardness) = V2 = (V * (DED – DEO)) / (DER DEO) Obviously we have V = V1 + V2
Example: We need to prepare 120L of water at 5 Β° TH, we have tap water with a hardness of 20 Β° TH and reverse osmosis water with a hardness of 0 Β° TH. We have: DER = 20, DEO = 0, DED = 5 and V = 120. This gives us:
V1 = (120 * (20 – 5)) / (20 – 0) = (120 * 15) / 20 = 90 Liters of reverse osmosis water (or mixed water). V2 = (120 * (5 – 0)) / 20 = 600/20 = 30 Liters of tap water.
Mixing 2 l of water of a given hardness with 1 l of water of a different hardness, result: 3 l of water of a hardness:
2 Liters of water with a hardness β¦
Mixed with a liter of water with a hardness β¦
Mixture hardness = (d1 * 2 + d2) / 3
Mixing 3 l of water of a given hardness with 1 l of water of a different hardness, result: 4 l of water of a hardness:
3 Liters of water with a hardness β¦
Mixed with a liter of water with a hardness β¦
Mixture hardness = (d1 * 3 + d2) / 4
Hardness of a mixture of X% osmosis water and water of nonzero hardness, result: water of given hardness at the intersection between the rows and columns concerned
Percentage of osmosis water (X%)
Mixture hardness = (X / 100) * Hardness
Conductivity
There is a relationship between hardness and conductivity, this gives:
1 Β° dGH = 38Β΅S / cm
1dKH = 30 Β΅S / cm
These relationships are only true if there are ONLY alkaline earth salts in the water (therefore no calcium and / or magnesium salt, therefore in fresh water, not brackish).
Nitrates NO3
Nitrites NO2
Oxygen saturation value as a function of temperature
The higher the temperature of the water, the more oxygen becomes scarce and the fish have difficulty breathing. Water at 30 Β° C contains 8.5% less oxygen than water at 25 Β° C.
Types of sand
Families compatible with your water
For more information on the different families of fish mentioned here, read the sheet concerning the classification of aquarium fish.
Temperature: Β° C / Β° F
Β° C = (Β° F – 32) * 5/9 Β° F = (Β° C * 9/5) + 32
Volume: US and UK
how many ounces in a gallon 
how many liters in a gallon 
how many quarts in a gallon 
how many cups in a gallon 
1 Liter = 0.264 US Gallon
1 US Gallon = 3.78 Liters
1 Liter = 0.2114 UK Gallon
1 UK Gallon = 4.73 Liters
Length: Meter / Inch / Foot / Yard
1 Meter = 39.4 Inches 1 Inch = 2.54 cm 1 Foot = 12 Inches = 0.3048 Meter 1 Yard = 3 Feet = 36 Inches = 0.9144 Meter
Weight: Gram / Ounce
1 Ounce = 29 grams
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