# quick question about lights



## offalmangler (Jan 17, 2010)

I picked up a new ballast and replaced my T10's with T8's

My question is on the bulb.
I have a set of aquarium specific bulbs for plants which gives off the different light, like a pinkish deal.

I also picked up soft white bulbs rated for 6500 kelvins.

The other bulbs have lumens ratings, but not kelvins.

Which one should i be using for a lightly planted 120 gallon tank?


----------



## Darkblade48 (Jan 28, 2008)

offalmangler said:


> I also picked up soft white bulbs rated for 6500 kelvins.
> 
> The other bulbs have lumens ratings, but not kelvins.
> 
> Which one should i be using for a lightly planted 120 gallon tank?


I think soft white is closer to 2700K than 6500K. 6500K are so called "Daylight" bulbs by most manufacturers.

As for the Kelvin rating on bulbs, it really isn't that important. Pick one that you like, and go with it.


----------



## offalmangler (Jan 17, 2010)

I think my question is being mis-understood.

I want to GROW my plants. I read that 6500k is optimum for this.

However, the other bulbs state aquarium planted tank specific with a different color temp. Most likely lower Kelvins.

All i would like to know is what would be recommended for plants, kelvins, or color?


----------



## Darkblade48 (Jan 28, 2008)

offalmangler said:


> I think my question is being mis-understood.
> 
> I want to GROW my plants. I read that 6500k is optimum for this.


Not true. See below.



offalmangler said:


> However, the other bulbs state aquarium planted tank specific with a different color temp. Most likely lower Kelvins.


Not true. See below.



offalmangler said:


> All i would like to know is what would be recommended for plants, kelvins, or color?


The Kelvin determines the colour of a bulb.

2700K is "warm white"
4100K is "cool white"
6500K is "daylight"

2700K is quite red/orange
4100K is more white
6500K is much more white, with a hint of blue
10000K has a noticeable blue tint

Plants do not really care what Kelvin rating the bulb is. The Kelvin rating is just how the light will appear to human eyes. In order to grow plants, the amount of (usable) light is more important than the colour temperature. As long as the colour temperature is under 10000K, plants will be fine. I have had success growing plants with a mix of 2700K and 6500K bulbs as well as just 6500K bulbs.


----------



## wiifish (Feb 10, 2010)

*Philips*

I picked up a shop light from Home Depot today along with 4 bulbs. Was dirt cheap compared to the Hagen GLO's I bought. I got the Plant and Aquarium T8 by Philips... it was very low K and I also picked up 2 6500k called Daylight Deluxe. The question was exactly what I was going to ask. The Aquarium and Plant one was very Pink (actinic). In the past I used one of each in a salt water setup....Not sure what will help me GROW plants, but I am afraid to use the wrong lighting and get a algae bloom if that even makes sense. Also I see a lot of Hydroponics places around the GTA which also carries T5 HO fixtures and bulbs which are a fraction of what LFS charges...wondering if it works for aquariums too.


----------



## Darkblade48 (Jan 28, 2008)

wiifish said:


> The Aquarium and Plant one was very Pink (actinic).


Actually, actinic is blue.



wiifish said:


> Also I see a lot of Hydroponics places around the GTA which also carries T5 HO fixtures and bulbs which are a fraction of what LFS charges...wondering if it works for aquariums too.


Why wouldn't they? 

It's not a big secret, but bulbs can be bought much cheaper at the hardware store than at the LFS.


----------



## wiifish (Feb 10, 2010)

> Why wouldn't they?
> 
> It's not a big secret, but bulbs can be bought much cheaper at the hardware store than at the LFS.


I came back to raising fish after a 15-20 year break. I've had fish since I was in grade 4...guppies in moms used peanut butter jar etc.... I guess since those days of old I was always told lighting was different and that it will cause some unwanted types of algae to grow so I should keep with the aquarium stuff. I guess I feel a bit insecure about that...but thinking again...Philips/GE etc...probably manufactures those LFS bulbs and are rebranded for all I know


----------



## BillD (Jun 5, 2006)

There are a lot of factors to consider when buying lighting. The So called plant and aquarium lights are pinkish looking because they have enhanced red and blue spectrum, in the wavelength plants supposedly prefer. They originated for growing terrestrial plants, and need to be very close to be effective. They have low light output compared to most other types of tubes. Light is an energy source for the plants, so higher output tubes are usually better. When they first came into the hobby about 40 years ago, people liked them because they enhanced the blues and reds on the fish. They have a lousy Colour Rendition Index, which means they don't show colours accurately, and a low light output. The higher the CRI, the closer to full spectrum a tube is. Sunlight has a CRI of 100, and a colour temp of around 5500K at noon at the equator.
A tube such as Philips Natural Sunshine, which is a 5000K tube has a CRI of around 92 or 94, while a Philips Ultra Daylight, 6500K, has a CRI of around 84. Both tubes will grow plants well and are quite bright. Both tubes are available at HD for around $4 in T8 (48"). Most major manufacturers offer similar tubes.
So, while plants will grow under a lot of different lights, you won't get the same results or growth rates from tubes that don't have the correct wavelength or light output, even though they may consume the same amount of electricity.


----------



## wiifish (Feb 10, 2010)

BillD....Very well said. Thanks


----------

