Tropical Fish Forums

[Flame Angel]

I've always been under the impression they should be changed about every 12 months, but I've never really knew much about them or understood properly why they should be changed. If someone who knows more than me on the matter questions it, probably worth listening to (especially if it can save you $$ )

[unissuh]

I tend to put more weight on hard data, no offense intended. People could be right in changing the bulb every year, but I really haven't seen the evidence to support this. Perhaps try checking the bulb specs that you are using, assuming the company provides the data sheets. If we were talking CFLs or power compacts then thats a different matter as the decay is much greater on these...but linear fluorescents now are pretty good.

I will admit that what the specs do lack is PAR values though. The decay specs are based on lumens, which is all well and good for the human eye, but doesn't definitively say how good they are for growing plants.
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[Flame Angel]