UV Bulbs-Ultraviolet Bulb For Koi & Garden Ponds

UV Ultraviolet Bulbs & Tubes

This replacement ultra violet light tube will fit many manufacturer's UVC units including Kockney Koi Yamitsu, Tropical Marine Centre, Evolution Aqua EvoUv and many more. Our Ultraviolet Tubes are High Grade Germicidal Bulbs by Osram, Written on one end of the uv bulb will be a code, it should say (G15T8) The first number is the wattage ie. 4,6,8,15,30,55, and the second is the size of tube ie. T5, T8.

UVs are used in the pond environment to 'kill' the microscopic unicellular algae that cause green water.

Ponds contain relatively large volumes of water requiring significant volumes to be pumped through a biofilter and UV. Consequently pond UVs come with fittings up to 2" in diameter with quite a wide diameter jacket around the tube to handle the required turnover.

The wattage of the UV must be geared so that the radiation is sufficient to denature the algae at a rate faster than it can reproduce. The radiation required to produce crystal clear water is below that of a sterilising action when the rapid flow rate is taken into account. Pond UVs can typically go up to 55W.

Consequently, to be more precise, these units are referred to as UV clarifiers rather than UV sterilisers. The distance between the quartz sleeve and the outer chamber will generally be greater than 10mm as they are designed to carry volume. This reduces the sterilising effect of the unit.

Adjacent to the pond the UV must be installed with a suitably sized biofilter with sufficient mechanical filtration capacity to remove excessive quantities of dead algae. Once installed, UVs are notorious for creating significantly more particulate waste and it is often wise to install an 'oversized' pond filter to remove the extra waste.

The UV radiation causes the microscopic algae to clump into 'flocs' of a filterable size. If these flocs are not removed then the floating detritus can often be less visually appealing than the initial green water problem. For this reason, the pump or drain should be placed where they rapidly remove the settled flocs of dead algae.

An unwelcome side effect of fitting a UV is that the nutrients (phosphates, nitrates etc.) in the water that are no longer fuelling microalgae growth can be utilised by macroalgae - particularly blanketweed. As blanketweed is not subjected to the UV radiation, then its growth may actually increase under the now improved conditions of enhanced light and freely available nutrients.