What is the best spectrum?

[sawyer1206]

I am still experimenting with my planted 20G and I have another question about the lights. What is the best light spectrum for a planted aquarium?

I first used 17W at 3500K and the tank was very dark.
I moved up to 17W 5000K and it looked better but I didn't stop there.
I tried some 17W 10000K I had left over from 200G project and I combined them with a couple 20W 18000K I bought today.

Can someone help stop the madness!!!LOL. What would be the best lamp or combination of lamps to use.

 

[180gz71]

Ive used from 5000K up to 10000k, and I personally like the 6700K look the best. Just my opinion though, I think 10000k and up just looks to whiteish, and the lower K's look to pinkish/yellow.

 

[phanmc]

If you want the absolute best kind of lights for plant growth, buy a PAR meter and test out the bulbs.

The color spectrum/kelvin rating won't tell you which bulbs are better for plants, though they will impact how the tank will look. Use the lights that looks best to you and don't worry about them being good or bad for plant growth, chances are they will grow plants fine if you supply enough wattage.

 

[skeletonhand]

Ive used from 5000K up to 10000k, and I personally like the 6700K look the best. Just my opinion though, I think 10000k and up just looks to whiteish, and the lower K's look to pinkish/yellow.

I agree. 6700K seem to be the best. The higher the kelvin rating will give you deeper penetration . With a 20G you won't need it though. I have fixtures that are just 6700K and one that is both 6500K and 10000K. The combo fixture gives a much whiter light

 

[DarkSoul]

I dont mean to sound rude or anything, but you guys are talking about the best spectrum for plants, but not a single one of you is talking about the right thing..... those are all just colour temperatures for the bulbs.

The colour temperature is merely the rating for the colour the human eye will see (the EXACT definition eludes me atm)

As for the best spectrum, I can't say personally for aquatic plants, since I have not grown them, nor do I have a fully functional tank currently.

What you should be looking at the is spectrum chart for the bulb, which will show you what specific wavelengths the bulb puts out (nm rating, not K)
then you need to find what spectrum the plants your growing require for thriving growth.

again, i apoligize if i've come off as rude or "know it all" im simply trying to correct misinformations.

Take a look at my thread
http://www.aquariacentral.com/forums/showthread.php?p=861570#post861570

loaches r cool posted some good charts there.