Is 12K light too high for plants?

**Blaze88** · 22nd Sep 2009, 20:22

Hi bros,

Here to ask on another noob question.

I just got my light set for my 2ft tank, 2X24W aquazonic

but when i open up the set, i saw that the tubes they have provided
are at 12K temperature

and from my readings, its said that plants absorb 5k-7k spectrum.
would that mean i would have to change the lights to a lower temperature?

please advice

**IlOutfitter** · 22nd Sep 2009, 20:52

Plants absorb all spectrums and all temp ranges.

what is the true capacity of your tank?

from there you can divide the total number of watts you have say in your case 48w divide that 48 by how many gallons of water the tank holds and that will give you the wattage per gallon.

I run 10k bulbs on my plant tanks, others I run 6500K the 10K grows more and grows fuller.

**Blaze88** · 23rd Sep 2009, 06:57

Hi bro,

Thanks for the reply,

Currently im having a 2ftX1ftX1ft tank so the volume would be around
15 gallons or 56 litres. do correct me if i am wrong.

thus having a 48watt, that would give me 3.2 wpg which should satisfy the 3wpg rule of thumb.

**IlOutfitter** · 23rd Sep 2009, 07:54

the 3wpg rule involves alot more then just lights, you will definetely need Co2 on that tank as well as things set on timers, 14.96 gallons is 15 gallons so that is right.

I run around 1.1wpg in my big 52g.

**bettaboy** · 23rd Sep 2009, 10:02

i think it should be okay for the plant, just that there would be more photosynthesis taking place.

**Blaze88** · 23rd Sep 2009, 18:28

haha thanks for the advice guys,

was afraid the bulb mite not be as good and be a waste of my power bills since several threads recommends the usage of 6-8K temperature bulbs

Also have spent quite alot on purchasing my new tank set so is best to keep the spending to a minimum else i mite be eating algae instead

Will post up the setting up of my tank soon, havent even started, will do it after my exam =D

**StanChung** · 23rd Sep 2009, 19:48

Do you like the colour of the light? If you like it then continue.

WPG is only accurate for 30X18X18 --> 36X18X18 --> 48X18X18 tanks.
Small tanks seem to have high WPG but that calculation is flawed.

A standard 2ft tank is ~24x12x14 and the mid point lighting intensity IMO is ~56-72W.
This is the point where glosso can grow but tend to be a little leggy.

HC would do fine.

Moss, crypts and ferns should have no problem at this intensity.

**Blaze88** · 23rd Sep 2009, 20:11

Hi StanChung,

Dang, i tot glosso would do quite well whereas HC not as much. That is why i have some glosso floating around in my balcony pond and in some plastic containers (aparently they even started growing new shoots though i can see that the leaves facing away from the light is starting to yellow)

So in order to have the glosso creap nicely in one thick layer i would require higher wpg huh. Would HC do fine in this lighting? I always thought HC qould require High lighting, High CO2 and Low Temp. Which is abit High cost to maintain for me

. Maybe ill get some HC to try it out as well.

I saw C328 selling HC in filtermedia thingy, would i have to remove the spongy substrate or just plant it ? Also are they emersed or submerged form?

**Tian85** · 23rd Sep 2009, 20:42

WPG is just a rough guage for how strong the light intense will be in your tank. For example, some plants might need 3wpg to stay short like HC. If you have a deeper tank then it will not be accurate. As for the 12k in light is just the temperature of the bulb. You will not burn your plants with just 12k of light. Choosing light is not just comparing the 'K' or Kelvin in the light but also the kind of specturm in the light. Some plant will absorb more blue while some absorb more red. For 12k light, it have more green in it so it will looks brighter but the green spectrum in the light is just for human visual, plant don't use the green spectrum in it for photosythesis. People will usually go for a 6500k or a 6700k light as it usually contain red and blue spectrum that is in the correct spectrum zone for the plants.

For green plants the lighting peaks that are most important:
Chlorophyll-a: 430nm/662nm
Chlorophyll-b: 453nm/642nm
Carotenoids: 449nm/475nm
Red pigmented plants use more light in the blue area of the spectrum.

If u want to know more you can refer to the link below as it mention more infomation on the light spectrum that is useful for plants.
http://www.aquaticplantcentral.com/f...osythesis.html

**StanChung** · 23rd Sep 2009, 22:05

Originally Posted by Blaze88

So in order to have the glosso creap nicely in one thick layer i would require higher wpg huh. Would HC do fine in this lighting? I always thought HC qould require High lighting, High CO2 and Low Temp. Which is abit High cost to maintain for me.

Yup, glosso's would need at least 100W for a 2ft to creep nicely. HC does need cool water to do well but it should do fine in 48W of lighting. Presumably it has enough usable PAR in it.

I saw C328 selling HC in filtermedia thingy, would i have to remove the spongy substrate or just plant it ? Also are they emersed or submerged form?

It's emersed, remove the media and plant in small 10-20¢ clumps.

**Blaze88** · 24th Sep 2009, 03:25

Wow 100 W ? Man that high ! haha, guess i would get some HC to try as well after all. The issue i guess would then be the temperature, won't be investing in a chiller, hopefully a fan can bring the temp low enough for HC growth