Display lights?

[lyquidphyre]

I am not happy with my tank right now, and i truely think its the lighting. Its one giant light bulb that I believe is 250 watts. It helps to grow plants and all... but the light is just so bright.
Right now I have natural gravel over my substrate (50lb bag for $10) and i asked what it looked like and the man said "its the same gravel used in our ciclid tank" and the gravel with a dark brown, very pretty gravel. When I opened the bag I was very pleased to see its dark color... but with my lighting, it turns the gravel yellow and I don't like it.
Is there anyway to set up "display" lights as wel as my "plant growing" light. So I can turn on one or the other at my own discretion?
When I have people over, turn on the lower, display lights but when in class I could have the "plant growing" ones on

any suggestions?

 

[TankGirl]

We need more info about the tank and the light itself - I can't remember what size your tank is. Is there is any description printed on the bulb? That will give us the info we need, hopefully. If not, we'll need to know how long the bulb is and the diameter of the tube if it is a standard fluoro, or a power compact.

In general, if you have light that casts a yellow hue in your tank then it has a relatively low K temp, and using a 6500K or something up to 10,000K will give a whiter appearance and be more (IMO) attractive. If your wattage is appropriate for the tank then you might just switch to a bulb with a higher color temp.

 

[malkore]

a 250w bulb sounds like metal halide, and if its a plant bulb, it probably is very yellow looking.

 

[lyquidphyre]

its a 75gal with a 250watt light bulb (from what i was told)
I looked on the bulb and it doesn't say anything specific.. its like 8in long and about 1.5-2in in diameter

What should I replace it with that will grow plants as well as the one I have right now?
I just want it to be a darker, simplier light. So it doesn't illuminate the gravel but the fish

 

[youronlysin]

Black light!! That does wonders to light up a fish! Haha...of course they look altogether different under black light, but cool nonetheless. Im keeping an eye on this thread...My gravel looks yellow under my 6700K CF bulbs too. Maybe not completely yellow, but it sure isnt as dark a brown as it was in the bag.

3.3 wpg is a good amount of light! I know when I upgraded from about 1.5 wpg to over 2.6 wpg, I really noticed things get more yellow. Im using the same kind of lights too, just a higher powered bulb. My plants sure like it though, they sprouted all over the place in a matter of hours when I added the extra light. I was thinking of adding a small actinic light for a reef tank. The small amount of blue wont do anything for the plants, but it might make the fish pop out at you. My blue moonlights make the fish almost glow.

 

[lyquidphyre]

i think you and I have the same light bulb and gravel =o)

 

[youronlysin]

Could be...my gravel was a natural kind of thing. I know when I washed it there was a fair amount of sand sized particles in it as well as bits of sticks or woody stems. It clouded badly, but cleared as I washed it. There was even a few pebbles here and there of different colors like some almost pink and some green; not epoxy coated aquarium stuff, just weird rock pieces. It really looks nice, but the added light really yellowed things up.

From your description, Id say your light is metal halide unit. I've never seen a bulb that was 250 Watts and only 8 inches long @ 1.2-2" in diameter. In the pics it looks like you have a lot of light, so Im guessing it is a metal halide bulb. Dont throw that away! Those bulbs are expensive!! I'd bet that is a 40-50 dollar bulb. Id try to find something else to add to it, or switch between the two, like you talked about earlier. Either that or find someone who might want to trade or buy the mh light from you and then get something different for yourself. That is a nice light to have though, for the plants, as long as its in the right spectrum. Does it produce a lot of heat? Dont touch it with your fingers...if you do, wipe it down good to remove any oils to make sure it will last.

 

[youronlysin]

I keep looking at the pic of your tank. That really is a bright light. Especially right in the center of the tank. Im almost positive thats a metal halide unit. Id say that is more suitable to growing coraline algae than it is plants , although Im sure it works fine for that too. Holy cats. That thing has to get hot! I dont know a lot about metal halide lighting, so maybe some of the saltwater gurus can tell you what kind of light might give you (us) better color. I can tell you that mine is 6700K CF and it still looks yellow once I got over 2 wpg.

 

[lyquidphyre]

It gets really hot. I have to put foil over the plastic hinge thingy on my glass or it will melt

And when I moved my plants... i pulled em out and put them on the glass and the water just steamed

 

[TankGirl]

Right - I am sure this is metal halide, and I am not experienced with that type of lighting for a planted tank. Malkore will know -

 

[malkore]

Hey, i'm not a MH expert either...I stayed with power compacts even on my reef tank. I'll see if another advisor can assist.

 

[fishfreek]

See if there is markings on your ballast. With MH you MUST match the bulb wattage with the ballast wattage. IE a 175W bulb will NOT work in a 250W ballast, etc. Once you can verfy the wattage of the bulb I take it this is a used setup. Do you have any idea how old the bulb is? MH bulbs should be replaced yearly. A quick and dirty on MH bulbs and their K ratings are below.

The higher the K rating the more blue specitrum in the bulb. The lower the number the more yellow the light will look. You might prefer a bulb in the 5000-6700K range. The inital coloration of the bulb will shift after the first 100 or so hours of operation.

 

[fishfreek]

This is probably WAY more info than you want but its good for you to at the very least skim to get an understnding. While these test photos show a SW tank you can get some idea as to what the different K ratings will produce as far as light output as well as that even different brands with the same K rating can produce different looks.

http://www.cnidarianreef.com/lamps.cfm

 

[lyquidphyre]

Thanks for the website fishfreek

I like the first picutre on the left under the "AB13K: Aqualine Buske 13000K"

*nod*
now to figure out where to get that

 

[youronlysin]

Looks cool to me. That looks expensive too! I wouldnt replace the bulb you have now with it though. I dont think that 13K bulb would do well for your plants, but I could be wrong. I think the peak wavelengths for photosynthesis to occur differ from plants to coraline algae. Im sure someone here has more experience there. That sure looked nice though....Did you see the pic with the 6700K light?? It was quite yellow compared to the bluer 13k.

 

[lyquidphyre]

Im gunna keep this bulb until it quits working.. cuz it is an expensive bulb

but i will definatly look into changing the lightbulb to a less yellowy light

 

[loganj]

A 6500k MH bulb is pretty yellow...the lower color temp bulbs are even more yellow in appearance. If you go up to a 10k bulb, you'll have a much whiter light...still very bright. If you get between a 14k and a 20k, you'll have a bluish tint to the lighting. I'm not sure if any of this is what you want though.

 

[loganj]

A little research has indicated that going above a 10k isn't the best option for plants. 10k will give you a nice white light though...some of them have a slightly yellowish appearance, but nothing like the 6700k bulb. If it's too bright, you might try a layer of window screen over the tank to cut the intensity a little.