There are a number of types of bulb used in pond lighting, and each lighting unit will employ a number of one type, usually wired into the mains via a transformer.

Standard Bulbs

Standard bulbs are the most commonly used, especially in older lighting models. Replacement bulbs are fairly cheap to buy and can last a few years. Standard bulbs tend not to be as bright as other bulbs, both in and out of water.

Halogen Bulbs

Halogen Bulbs are superior to the standard bulbs in terms of brightness and lifespan, although the bulbs are slightly more expensive to buy. They are excellent at lighting underwater, as the wave-length of light they produce travels extremely well through water.

LEDs

LED lights are brighter than all other bulb types when run out of the pond, they also boast an impressive lifespan and are very cheap to run. However, they tend not to be as bright as Halogen bulbs if submerged as the light they produce doesn’t travel as well through water.