Question about my lights

darkfalz · 11-14-2007, 10:16 PM

My tank has three lights, 2 x 25 watts and 1 x 20 watts

The 25 watts are 8000 kelvin and look natural colour and are bright. The 20 watts looks purplish and is 15000 kelvin. Are the 8000s for plants and the 15000 for coral or something like that? Or is that purple spectrum good for plants?

**JustOneMore20** · 11-15-2007, 07:51 AM

Yes, usually Kelvin ratings 10000K and above are for reef tanks. They usually use the blueish/purpleish lights on their tanks.

I suggest replacing it with something in the 6500K to 10000K range. 8000K is perfect for plants.

**Damon** · 11-15-2007, 11:17 AM

10000K is fine for planted tanks but any higher is a waste.

darkfalz · 11-15-2007, 12:01 PM

Confusingly the small light on my 10 gallon tank claims 18000 kelvin but is only slightly purple, and I have two of different strenghts of tube (20 lux vs 30 lux).

**Damon** · 11-15-2007, 01:41 PM

Not all bulbs are created equally. Also bulb life has a lot to do with par and color. Older bulbs may not show a color change (some do) but the spectrum does change. 18000K may appear purple to you but may appear bluish to others. K is the color we perceive and everyone's eyes are different. I would still change it to a lower K (6500K-10000K) and change all bulbs every 6 months for peak efficiency.

11-14-2007, 10:16 PM	#1
darkfalz Vishy vishies! Join Date: May 2006 Location: Australia Age: 29 Posts: 476 User Feedback: (0)	Question about my lights My tank has three lights, 2 x 25 watts and 1 x 20 watts The 25 watts are 8000 kelvin and look natural colour and are bright. The 20 watts looks purplish and is 15000 kelvin. Are the 8000s for plants and the 15000 for coral or something like that? Or is that purple spectrum good for plants? __________________ 40L planted - 1 (opaline?) gourami 160L planted - 9 harlequin rasboras, 3 platys, 3 swordtails, 1 guppy

11-15-2007, 07:51 AM	#2
JustOneMore20 Moderator Join Date: Apr 2006 Location: Alabama, US Age: 22 Posts: 3,366 User Feedback: (2)	Yes, usually Kelvin ratings 10000K and above are for reef tanks. They usually use the blueish/purpleish lights on their tanks. I suggest replacing it with something in the 6500K to 10000K range. 8000K is perfect for plants. __________________ *Kristin* 5 Planted tanks: 55g, 40g, 29g, 10g, 5.5g 10g N. multifasciatus tank, 5.5g Platy fry

11-15-2007, 11:17 AM	#3
Damon Aquatic Naturalist Join Date: Jan 2005 Location: Dayton, Ohio Age: 32 Posts: 14,982 User Feedback: (0)	10000K is fine for planted tanks but any higher is a waste. __________________ For in much wisdom [is] much grief: and he that increaseth knowledge increaseth sorrow. Member of the AGA (Aquatic Gardner's Association) Member of the IBC (International Betta Congress)

11-15-2007, 12:01 PM	#4
darkfalz Vishy vishies! Join Date: May 2006 Location: Australia Age: 29 Posts: 476 User Feedback: (0)	Confusingly the small light on my 10 gallon tank claims 18000 kelvin but is only slightly purple, and I have two of different strenghts of tube (20 lux vs 30 lux). __________________ 40L planted - 1 (opaline?) gourami 160L planted - 9 harlequin rasboras, 3 platys, 3 swordtails, 1 guppy

11-15-2007, 01:41 PM	#5
Damon Aquatic Naturalist Join Date: Jan 2005 Location: Dayton, Ohio Age: 32 Posts: 14,982 User Feedback: (0)	Not all bulbs are created equally. Also bulb life has a lot to do with par and color. Older bulbs may not show a color change (some do) but the spectrum does change. 18000K may appear purple to you but may appear bluish to others. K is the color we perceive and everyone's eyes are different. I would still change it to a lower K (6500K-10000K) and change all bulbs every 6 months for peak efficiency. __________________ For in much wisdom [is] much grief: and he that increaseth knowledge increaseth sorrow. Member of the AGA (Aquatic Gardner's Association) Member of the IBC (International Betta Congress)

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