Tank Calculations & Measurements
Despite the metric system, you can still expect to come across weights and measures that are unfamiliar. I've tried to list everything I think is useful for fishkeeping. You may find this page useful for conversions and setting up and stocking your tank.
Tank Measurements
Length:
1 meter (100cm) = 39 inches.approx.
1 foot = 30cm approx.
To convert cm to inches, multiply by 0.4
To convert inches to cm multiply by 2.54
Volume:
This is measured in litres, To measure volume, multiply depth by surface area.
Volume = length x width x height
1 litre (1000cc) = 1.75 pints
5 litres = 1.1 gallons approx.
To convert litres to gallons, multiply by 0.22
To convert gallons to litres, multiply by 4.56
Weight:
This is measured in kg's. The weight of water is equal to the volume in litres.
To convert kg's to pounds (lb's), multiply by 2.2
To convert lb's to kg's, multiply by 0.453
Temperature:
Celsius (C) and Fahrenheit (F) are used to measure temperature.
To convert Celsius to Fahrenheit, C = (F - 32) x 5/9
To convert Fahrenheit to Celsius, F + (C x 9/5) + 32
Hardness:
This is measured in degrees, DH. Here's a general guideline for fish and water hardness.
Freshwater:
Very Soft 0-6DH = Suits Barbs, Characins, Discus, Killifishes
Soft/Medium Hard 7-15DH = Suits Catfishes, most Cichlids, Goldfish, Gourami & Loaches
Hard 15 DH+ Suits African Cichlids, Livebearers
Brackish:
(1tsp salt per 5 litres+) = Mollies, Monodactylus, Australian Rainbowfish
Marine:
S.G. 1.023 = All tropical and coldwater saltwater fish & invertebrates
Alkalinity/Acidity:
The Ph scale is used when measuring this.
Neutral = 7 Ph
Acidic = Below 7 Ph
Alkaline = Above 7 Ph
Tank Measurements and Livestock:
A 90cm long tank is the smallest size recommended for tropical marine fish, although you can have coldwater invertebrate tanks in smaller sizes.
Each cm of a fishes' body requires the following surface area:
30cm sq in tropical freshwater
75cm sq in coldwater freshwater
120cm sq in tropical marine
Here are a couple of examples for calculating your livestock capacity:
Tank Size: 90 x 38 x 30cm
Volume: 102.6 litres
Total body length (Trop. Freshwater): 90cm
Total body length (Cold Freshwater): 36cm
Total body length (Marine):Tank Size: 23cm
Tank Size: 120 x 38 x 38cm
Volume: 136 litres
Total body length (Trop. Freshwater): 120cm
Total body length (Cold Freshwater): 48cm
Total body length (Marine): 30cm
You can make your tank seem deeper by adding a backdrop, or even just some coloured card. This often improves the visual effect of your tank and allows you to see your fish better.
