Can these phosphors burn out sooner and shift the spectrum well before the base direct LED gives out? Is there a guesstimated general timeline on that?
Hi Jason, you are correct.
The phosphorus material degrades over time.
This depends on various factors... some examples:
The wavelength of the basepump --> The lower the basepump wavelength, the higher the energetic content per photon and the more destructive for the material.
The type of phosphor --> multiple phosphors are used to create white colors (e.g. the 3000K I referred to before). Each phosphor has its own properties and is more or less robust towards aging.
e.g. the phosphor that is used to generate the blueish wavelengths in fluorescent T5 lamps suffers from the mercury peaks (basepump) and degrades much faster compared to the other phosphors.
Therefor the color point of a T5 tube shifts over time (because the blue part of the spectrum is reduces (and slightly shifted). These blue wavelengths are very important for our Corals growth and this is the main reason you are advised to replace your T5 lamps every 6-12 months. You do not perceive a big drop in brightness, but for the coral the most useful wavelengths are reduced drastically.
The overall junction temperature of the LED and operation temperature of the phosphor --> Overdriving LED's or having poor cool will increase the degradation process.
It is hard to set a general timeline (due to the amount of variables). It can be from 10.000 hours (poorly designed) to 100k hours (industrial graded).
