T5 light question

[hani]

HI,
I know its been demonstrated before that the par reading between a 6 month old tube and a new tube in not that significant, my question: does the light spectrum change over time? are both tube emitting the same spectrum after 6 month?
thanks

 

[Biollante]

PAR Is PAR

Hi Hani,

Yes the wavelength, the spectrum does change. :gw

The first to go are the UVA (400-320 nm) and UVB (320-290 nm).

Thankfully for those of us with planted tanks the spectrum we are interested in lies in the 400-700 nm range.

In my ever-humble-potted-plant opinion as long as the PAR value remains the lamps are good.

Biollante