It is very important to replace the UVB lamps regularly

We are often asked how UVB levels decrease over time. Unfortunately, it is a fact: UVB radiation decreases over time and the terrarium lamps have to be replaced. The combustion processes in the glass flask produce waste products that accumulate on the inside and act like a filter. Our experience is that the bulbs should be replaced after 3000-3500 hours of operation at the latest. Then they only have approx. 25% of the original UV output. However, visible light and heat radiation remain the same.

To find out, we ran long-term tests and took the average values ​​of at least 50 lamps per wattage. Individual lamps can be outliers, since all metal halide lamps are produced by hand and therefore there are certain fluctuations. However, they are so small that they are not relevant in practice. Here is a chart of the long term measurement (UVB loss) for 70 watt lamps. The curve looks similar at all wattages. After about 5 months (8-9 hours per day) the UVB value was 40% of the initial value and after a year it was about 25%.