There are many types of ultraviolet lamps. Bulb-type ultraviolet lamps and searchlight-type ultraviolet lamps can only irradiate ultraviolet rays to a certain point. Tortoises do not necessarily climb to a position where the light outside the purple line can be irradiated, so the effect of ultraviolet rays is not satisfactory. The fluorescent tube-type ultraviolet lamp can irradiate the tortoise's entire range of activity, that is, the entire terrarium, so the fluorescent tube-type ultraviolet lamp is better. The fluorescent tube type ultraviolet lamp can irradiate the entire box, but its disadvantage is that the effective irradiation distance is very short. The ultraviolet rays it emits can only reach within 25 centimeters, and there will be no effect no matter how far away. If the box in which the UV lamp is installed is very tall (very deep), the specially installed UV lamp becomes an ordinary fluorescent lamp. In addition, if the UV lamp is too close to the tortoise, it may turn the tortoise over. So be sure to install the UV lamp in the proper position.