FL light tubes

[taz_boy]

just a question,

i've seen many different brands of FL light tubes in LFS, the price of the tubes varies from $3- $10++, wonder how come there's such big difference...

cos i'm thinking of changing a 18W FL tube, normal hitachi type only cost $3 buck plus...anybody know how many "k" are they?

those Atman brand cost much more cos they are 10,000k...but as far as know, the "k" only mean the diffference in color spectrum rite...does it affect how deep the light can shine into?

[XnSdVd]

Well... red light travels the shortest distance and blue travels furthest. But i have no idea if 10,000K lights produce more blue and less red or just more blue. K stands for kelvins by the way, it's the temperature that the filament burns at. So "cool white" is actually alot hotter than a "warm orange".

[juggler]

For planted tanks, those rated "daylight" tubes (not "cool white" or "warm white" etc.) should be sufficient.

I used to have AEC or Elibru PL tubes rated 6500K and now I am using Osram PL 6000K. These are "daylight" temperatures. I get mine from hardware stores, not the LFS.

[taz_boy]

so my query is, does higher "k" mean that the light can shine deeper?

[solonavi]

No. Kelvin is juz the temperature of the spectrum. Penetration of the lights will depends on its lumens.

For detailed explaination, try this. http://aquaticconcepts.thekrib.com/Lights/

Cheers
JC

[taz_boy]

THANKS SOLONAVI,

the uncle @ the LFS tok cock, say wat higher kelvin can shine deeper, then i was scratching my head, cos i nv hear b4 such things.....

[sherchoo]

Kelvin does not define how deep the light travels so pay no attention to that. Generally, light looses intensity as the light travel further. Flourescent is said to go as deep as 2ft with minimal loss. So tanks with not more that 2ft deep should not be a problem.

As the K increases the light will be more bluish. At 10,000K you'll notice a bluish tinge in the light. People avoid this range as it promotes algae (wonder if this theory still valid). Anyway, 6500K (daylight) is an ideal temperature for planted tanks.

Tubes with the same K rating sometimes do vary in the price. This is due to the lumens rating which basically has has more light intensity.

[taz_boy]

oic.......thanks a lot sherwin..so do they specify the lumens on the light tubes or anywhere....cos i need a 18W with high light intensity

[sherchoo]

oic.......thanks a lot sherwin..so do they specify the lumens on the light tubes or anywhere....cos i need a 18W with high light intensity

Most tubes dun indicate the lumens specs. Reputable brands might have it but dun depend on that. Specs only can be seen on catalogs.

[XnSdVd]

But it IS true that blue light travels deeper than red light. So the uncle is partially right. Of couse you plants don't use much blues or reds but mostly greens. So the uncle is probably full of cock...

[PeterGwee]

Doesn't really matter with the K rating...anything from 5000-10000 works well. Plants are more adaptable than folks think. 10000K bulbs don't cause algae issues... Thats a myth.

Regards
Peter Gwee

[Justikanz]

Sorry, Shannan, you got it opposite. Plants use blue and red for photosynthesis and reflect green. That's why plants are green.

[solonavi]

Sorry, Shannan, you got it opposite. Plants use blue and red for photosynthesis and reflect green. That's why plants are green.

[XnSdVd]

Bah... I feel stupid. Though you keep getting my name wrong, it's Shannon

[aqualover]

Sorry, Shannan, you got it opposite. Plants use blue and red for photosynthesis and reflect green. That's why plants are green.

Yeah, read it somewhere about why plants or their chlorophyll appears green.
And for some reason, freshwater plants absorb pink light better and marine corals absorb blue light best.