Lighting/Hood QInquiries

[KentCurtis]

Hey everybody. I have a 20 gallon high tank and with it came a 24" full hood with a fluorescent bulb. Somehow I got a crack in my hood on the left side and was already thinking of getting a new one for lighting purposes. I am a newbie and don't really understand how the hoods/bulbs work. Im looking to make a planted tank out of this 20g, right now the hood is "19 watts" and the bulb in it is "15 watts". I asked in another thread about bulbs and was told to get "anywhere between 5000K and 10000K color temperature" for my tank. What im getting at is that I need a 24" hood that can support that kind of bulb. It wont be HEAVILY planted, but I am looking to get a decent hood/light. The lights I have found are all 20w - 40w but I cant find the measurements on hoods ive looked up online. Can anyone give me some suggestions? Thanks all, sorry about the lengthy and possibly confusing post

[runninwoof]

oky doky

u have a 15 wat bulb over your tank now.
that is pretty low for plants in a 20high.

i would get a incondesent hood and use 2 compact flouresent bulbs! maybe 25 watts each at something greater than 5000k! very cheep and grows plants well

[KentCurtis]

Thanks. Whats the difference between fluorescent and incondesent? I thought fluorescent was the way to go for plant growing

[OldMan]

A fluorecent bulb will put out more light for each watt of power than an incandescent light bulb. The old fashioned screw in light bulbs that get hot are called incandescent. The reason to get an incandescent hood is because they will have places to screw in 2 bulbs and if you use fluorescent bulbs in those, the new spiral type, you can get more light into your hood than using the fluorescent. In a particular length, all fluorescent bulbs have the same wattage rating so swapping around spectrum temperature won't do much if anything to improve plant growth. Another way to get more light going into the tank is to buy an upgrade kit to go from standard fluorescents to power compact fluorescents. The price of a new incandescent hood plus the new bulbs will be almost as much but not quite as a real upgrade kit from a place like AHSupply. I have done upgrades using their kits and the end result was much better light and a very professional looking finished product.

[CHBGator]

Originally Posted by OldMan

A fluorecent bulb will put out more light for each watt of power than an incandescent light bulb. The old fashioned screw in light bulbs that get hot are called incandescent. The reason to get an incandescent hood is because they will have places to screw in 2 bulbs and if you use fluorescent bulbs in those, the new spiral type, you can get more light into your hood than using the fluorescent. In a particular length, all fluorescent bulbs have the same wattage rating so swapping around spectrum temperature won't do much if anything to improve plant growth. Another way to get more light going into the tank is to buy an upgrade kit to go from standard fluorescents to power compact fluorescents. The price of a new incandescent hood plus the new bulbs will be almost as much but not quite as a real upgrade kit from a place like AHSupply. I have done upgrades using their kits and the end result was much better light and a very professional looking finished product.

Thats not correct. What you just told him is that a 3K bulb will grow plants just as well as a 6700K bulb will. Plants need the full spectrum of light in order to grow properly. Sunlight at mid day is 5500K and 6700K at the equator with a clear sky at noon.

[OldMan]

I am well aware of the difference in color spectrum and also have seen the results of research that basically says the light intensity is the main factor influencing plant growth unless you start getting into ridiculous color spectra such as a black light might have.

[CHBGator]

Originally Posted by OldMan

I am well aware of the difference in color spectrum and also have seen the results of research that basically says the light intensity is the main factor influencing plant growth unless you start getting into ridiculous color spectra such as a black light might have.

Can you be a bit more specific? I have a feeling I know what your getting at and even with that Color spectrum still plays a major role in plant growth not just "intensity". If wattage was the only factor then Incandescent would work just as well.

[SpeedEuphoria]

If your going for CO2, then this would be a great light, not crazy wattage and nice bulbs/reflectors, T5HO is where its at on lighting for aquariums at this time(till led's are cheaper).

Nova 24"

A better price from here(but the site is down currently)
Current USA Nova Extreme T5 HOx2


If you can DIY, PM me and I'll give you some links to nice parts for a single or 2x 24w T5HO and great reflectors

[OldMan]

I think the link I found to the research was from Rex's forum location. It amounted to a set of research data that looked at many dozens of different bulbs and their spectra with an assessment of the ability to grow plants. The essence of it was that the light that we perceive is not what the plants use to grow and that the light intensity, not visible spectrum, was the main factor in promoting plant growth. There is just plain more light energy coming from a fluorescent than an incandescent at a given electrical power input because the fluorescent bulb converts electrical energy to light energy more efficiently. The trouble with lamp spectra is that they are focused narrowly into some extreme peaks at the energy levels where the fluorescing elements emit light. If the spectral lines are the right energy, the light is a good one for plants. If the light looks the same, has the same spectral temperature, but has its energy peaks at the wrong wavelength, it is not so good for plants. Unless you actually analyze the spectrum of the bulb that you propose to use, there is nothing intrinsically better about a 3000K bulb over a 6700K bulb as far as growing plants. You might as well pick whatever is cheapest. The research also cited some experiences of the author with low spectral temperature lamps that showed plant responses about the same regardless of the temperature of the bulb chosen.
Personally, I like the 5500K and 6700K bulbs because I like how they look. With what I have read, I don't kid myself into thinking that I have somehow chosen the ideal bulb for my plants.