Here is a calculation of the cost. How much will be saved if you choose LED lights? Take the seawater aquarium 120 * 60 * 60 for example. For the product with similar specifications and operation time of 6,000 hours (about two years) is shown as below:
  A. To meet normal lighting requirements, 600W special aquarium sodium bulbs with unit price of RMB 500 are used.
  1. Cost for purchasing light bulbs: 6,000 hours of use. The bulbs should be replaced two times due to its service life limit. Cost: 2 ¡Á 2 ¡Á 500 = RMB 2,000
2. Power consumption fees: 6,000 hours of use. The price is RMB 0.8 per kilowatt-hour. Total payment of power consumption: [(600 ¡Á 6,000) / 1000] ¡Á 0.8 = RMB 2,880
Total cost: RMB 4,880
  B. If LED lights (service life reaches to 40,000 hours) are used, one 180W LED light (including power supply) is needed for achieving the same light output by sodium bulbs. The unit price of LED light is RMB 6,200. 
1. Cost for purchasing LED lights: 6,000 hours of use without replacement. Cost: (6,200 ¡Á 1) / 16 = RMB 387
2. Power consumption fees: 6,000 hours of use. The price is RMB 0.6 per kilowatt-hour.  Total payment of power consumption: [(180 ¡Á 1 ¡Á 6000) / 1000] ¡Á 0.6 = RMB 640
Total cost: RMB 1,027
  According to the result of above calculation, about RMB 5,773 can be saved for power consumption fees within two years if you choose LED lights and use it properly.