Sarah wrote in message
...
Anyone know when a Hagen Aquaglo tube should be replaced?

The website claims a life of 7500 hrs, so when the tube is used 14 hrs a
day
would be a life of around 18 months.

Some research on the net suggests that the output of the tube rapidily
decreases with age for some tubes, some tubes however (such as the triton)
run at near full output untill they fail.

Does anyone know which theory applies to the Hagen Aquaglo?



Some bulbs are meant to fail when they are at their usable end.
The majority of the others tend to gradually fade over time. The quoted
life of a bulb indicates when it could be expected to 'burn out' and no
longer function. But as the bulb is getting weaker as it ages, the usual
advice for maintaining optimal efficiency is to replace it around the one
year mark.

Jim