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Re: Lighting



Hi all ,

I am new to this list and to aquariums in general so please bare with me.

I see a lot of 'talk' about colour temperature and plant growth and, as
said, I am new to aquariums, but I am  not new to the use of artificial
light for plants.

My problem is that in all my years of reading about and using artificial
light on plants , I have never seen the colour temp referred to as a guide
to the suitability of a given lamp for plant irradiation.

 In fact to use an example, the 10000k ,[blue sky] ,so often referred to,
has a spectrum peaking in the blue end of the daylight spectrum whereas the
action spectrum for plant growth runs the other way.

Plants do not need much blue light -5% to 10% of the total; it controls
shape and is significant to general health. Actually the peak for
photosynthesis  is in the red side of the spectrum at about 675nm.

Philips Lighting do not recommend or advise the use of MH or Mercury lamps
for plants, and I have observed some pretty weird affects from these lamps
when used for total replacement lighting: stunted and distorted growth, to
name just two.

Sorry for the long post; as I said, I am new here and have come to learn -
am not trying to teach old dogs new tricks!!  So could somebody please
clarify the use of these lamps. I am, of course, aware of the aesthetic
advantages of the lamps in question.

Best wishes,

Steve.