Useful numbers, parameters, calculations, estimates, general-rules-of-thumb.

1/2 cup salt mix per gallon of fresh water = 1.025 sg

1 gal of water = 10 lbs of dry weight (8.35 lbs to be more exact)

Recurring Costs, Maintenance & Reserves
   Cost of operating a motor vehicle = $.50 to $1.00 per mile
   Change T5 ($20/bulb), and MH ($60/bulb) light bulbs every 1 year
   Change LED bulbs every 3 to 4 years
   Change pumps every 3 years
   Change water, 10% every 2 weeks @ $1.00 per gallon
   Change RO/DI filters every 6 months to 1 year
   Electricity = $.15 per kwh
   Electricity cost per 250watt MH HQI bulb = $13/month if on 8 hrs/day at $.11/kwh
   Food
   Supplements

Water Parameters & Quality
   Salinity = 1.025 sg at 78F, or 35 ppt (parts per thousand)
   Temperature = 80F
   pH = 8

Lighting
   Use one metal halide bulb for 24" of tank length.
   2 to 5 watts of lighting per gallon of water.
   PAR value of 100 at the bottom of the tank, will be more PAR higher in the tank
   Temperature near 250watt MH HQI bulb = 350°F

Stocking
   2" to 3" of fish per 10 gals of tank size

Live Rock
   1-2 lb (.45 to .9 kg) of live rock per gallon (US) (~ 4 liters) of aquarium water depending on the density of the rock.
   Fill the tank up 1/2 to 2/3 of the way to the top.