Lighting Question

[macfisto]

Hello everyone,

I set up my new 55 gallon about a week ago and am going to put some live plants in it. I just ordered a very low-light selection yesterday from freshwateraquariumplants.com. I plan on using only two 15 watt bulbs for a total of 30 watts, because this is what my current hood will hold. Since the tank is in a prominent spot in my living room, I do not want to put a shop light on it. Anyway, my question deals with the type of bulbs I should use. Last night, I purchased two Philips "Natural Sunshine" bulbs at Home Depot. They are 5000K and have a 92 CRI. Now I see that Philips also makes a "Plant and Aquarium" bulb, but the K and CRI values are not listed. Which bulb would be better to grow plants? I would appreciate any advice.

Thanks,
Rob

 

[malkore]

Either bulb is going to grow plants fine, though 5000K is a bit yellow to the human eye and may not look good.

I hope you didn't order anything beyond java ferns, crypts, or anubias bartari. at .5wpg you're severely limited on what you can grow.

 

[macfisto]

Thanks malkore. Do you know what the K and CRI values of the aquarium bulb are? I did notice that the 5000K bulb was quite a bit more yellow than the All-Glass ones that came with the tank. Are you saying that the aquarium bulb would have a higher K value and thus be less yellow? And yes, Don at freshwateraquariumplants did say that he would be sending me mainly java ferns and anubias.

Thanks

 

[malkore]

Kelvin is only a measure of the color produced when shone on a special black background. In other works Kelvin is how the light looks to our eyes, but not a measure of how useful the light is to plants.
The CRI (Color Rendering Index) is a better gauge of that. Don't quote me but I think natural sunlight is considered CRI 100.

However what it honestly boils down to is intensity of lighting. You could have a bunch of 3,000K bulbs with a CRI of 80, but if you have 3.5watts per gallon worth...you'll grow anything you want. But if you have 1wpg of CRI 95 and the most common kelvin 6500K, you're super limited to what you can grow. Plants will make use of whatever light you give them, and if it's enough intensity, the plants will do well.

 

[greenmaji]

It sounds like you have two small NO strips.. Light intensity is going to be a problem.. Your options are buying new light strips that are CF or over driving the NO with a larger electronic balast.. if your intresed in the later do a search for ODNO in the forums here.. Ive posted quite a bit about it..