Converters Temperature Distance  °F   =    °C    in  =    cm Flow Rate Water Hardness   gph  =    lph   °dH  =   ppm Volume  US Gallons  =    Liters  =    UK Gallons Calculators Pounds of Gravel Needed Please enter the length and width of your aquarium base and the depth of the gravel bed you require. If you know the weight of your substrate, enter it in the pounds per cubic foot field. Length Pounds per cubic foot Width Pounds Needed Gravel Depth in Measure Rectangular Volume Measure Cylindrical Volume Please enter the length, width, and height of your aquarium. Inches Centimeters Length Width Height Volume   US Gallons   Liters Please enter the radius and height of your aquarium. Inches Centimeters Radius Height Volume   US Gallons   Liters Estimated Monthly and Annual Electrical Costs Please enter the total wattage per appliance type used as well as the number of hours used per day for each appliance type. Cost per KWhr: $  US Dollars Equipment: Total Watts: Hours Per Day: Cost per Month: Cost per Year: Filters Pumps Powerheads UV Sterilizer Heaters Lighting 1 Lighting 2 Other 1 Other 2 Total Watts: Average Cost per Month: Total Cost per Year: