# Lighting Question



## jshank (Aug 16, 2008)

I have live plants and want to up the light in the tank because I am pretty sure its not getting near enough. The plants in it do okay but I am sure they could be better. They are pretty light, not a real dark color. Anyways, I don't really want to get new hoods so I was wondering if there is a better bulb I can get. My current setup is a 2 part hood (55 gallon tank). They both have 15 watt bulbs. There are bulbs that are suppose to be better for plants, are those good to use or what should I use?? Anyways, any help would be great. Thanks!!

Jon


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## djrichie (May 15, 2008)

If it's a 18 watts light sysytem the best your going to with that is 18watt bulb You are going to have to upgrade the light system if you want more Watts Per Gallon (WPG). You can do that and keep the same look buy buying fixture that fit you exixting hood, they sell t-5 and CF lights that have that same tradtional plastic hood look at petsolutions.com. The other thing is you could but glass hoods for the tank and buy a new light all together. You could also try and DIY some CF household bulbs into the plastic light housing you have already.


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## budcarlson (Feb 3, 2009)

I also have a 55 with glass hoods, 2 fixture 18" 15W Tropic Sun 5500K bulbs. I have read that aquatic plants really need about 1W/gal, and ideally 2W/gal. In that case, I would need to have 2x25W bulbs and ideally 2x50W. I don't even know if the fixtures are made for that wattage, and where would I get the bulbs? Local pet stores? Or can I just get your everyday Home Depot bulbs?


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## djrichie (May 15, 2008)

you have to use the the wattage that is required by the fixture transformer. You can by bulb at home depot but make sure they ar datlight bulb a k rating of 6500 to 6700. As far your light on the 55 gal tank you only really have 18 watts for the whole tank as the bulb are split into 2 fixture. I would recommend gettting a new lighting system. and get 2to 3 WPG if you wnat to do a planted tank.


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## budcarlson (Feb 3, 2009)

So is that just BS advertising on the part of Zoo Med Aquatic, the maker of Tropic Sun bulbs when it says

'Balanced trichromatic full spectrum daylight lamp, which simulates natural sunlight'
'Ideal for freshwater fishes and live plants'

Why is a 6500 Kelvin of 6700 Kelvin bulb better for your plants if 5500k is 'ideal'. Also how does 2x15W only equal 15W. If it was one continuous bulb, twice as long, to put out the same light intensity it would have to 30W no?


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## archer772 (Nov 8, 2008)

budcarlson said:


> So is that just BS advertising on the part of Zoo Med Aquatic, the maker of Tropic Sun bulbs when it says
> 
> 'Balanced trichromatic full spectrum daylight lamp, which simulates natural sunlight'
> 'Ideal for freshwater fishes and live plants'
> ...


The spectrum of those bulbs are ideal but you would need more than just 1 bulb. I think the 6.5k bulbs will deliver the best par for your plants but that doesnt meen you cant use bulbs from 5.5k up to 10k. The thing about the 15 watts I assume is because you only have 15 watts per side.


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## budcarlson (Feb 3, 2009)

archer772 said:


> The thing about the 15 watts I assume is because you only have 15 watts per side.


I get that, but as an engineer it doesn't make sense to me. If I had a 27.5 gallon tank with a 15W bulb, I have 0.54 w/g. If I put 2 27.5 gallon tanks next to each other, each with 15w bulbs, each tank has 0.54 w/g. So how can 1 55g with 2 15w bulbs have _less than _0.54 w/g. It would be 30w/55g = 0.54 w/g. Why would it be _half _that?


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## archer772 (Nov 8, 2008)

Because a 30 watt bulb puts out 30 watts from one end to the other


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## budcarlson (Feb 3, 2009)

Ok, same issue. If I have an 18" 15W bulb, then I'm getting .83 watts/inch of bulb. If I have a 30W full-length bulb (36") I get .83 w/in of bulb. A 15W bulb doesn't lose half it's output because it's half the length. I have a combined total wattage of light infused into the aquarium regardless of how many lights are actually present.


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## DarkRevoultions (Sep 5, 2008)

Is 18 watts even okay enough for aquatic plants in a 55 gallon?

I have 20 watts, and 6,700 Kelvin. 

I have green hedges, and amazon swords. Regular fluorescent lighting is okay for some type of plants because they don't require strong light. Crypts, anubias and other type of really small plants that are adapted to low lighting conditions.

Also, normal fluorescent lighting does not help enough with the photosynthesis cycle. 

You might think "Well how come the sun can do it?" The sun is a main powerful source of light which has different levels of UV rays. Well I think the sun produces ALL of the UV rays for both Aquatic life, and land life plants.

Also, the 20 Watt fluorescent tube with 6,700 Kelvin rating is fairly good. Although in my other tanks, I have 10,000 Kelvin rating which is extremely good for big huge planted tanks. Like 55 gallons and more.

Although I would want to get an extremely bright light bulb that could illuminate the ground too that can give a little bit of light with small low lighting plants if you get what I mean..

Most plants in the wild usually get from 10 - 12 hrs of light and at some places get even more.

I give my plants about 13 - 14 hrs of light a day. Since I wake up at 7:00AM and turn the lights off at 11:00 PM.

You may see that fishes in the wild are very bright. Why? because of the sun. There are special lights that can help with coloration of the fishes.

Good luck


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## Stellaluna (Jan 20, 2009)

The bottom line here is that you can grow hardly any plants well with the standard light hood over a 55g. Does not matter what bulb you use. The intensity is too low. The proof is in the pudding, so to speak. 

The most economical way to go is to get a shop light, which would have two 4' bulbs and that would be just about right. You will see the difference in how the plants grow, and it is a very inexpensive solution. 

More light gives algae a chance to take over, so fast-growing stem plants will help utilize nutrients in the water to keep this from happening.


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## DarkRevoultions (Sep 5, 2008)

Stellaluna said:


> The bottom line here is that you can grow hardly any plants well with the standard light hood over a 55g. Does not matter what bulb you use. The intensity is too low. The proof is in the pudding, so to speak.
> 
> The most economical way to go is to get a shop light, which would have two 4' bulbs and that would be just about right. You will see the difference in how the plants grow, and it is a very inexpensive solution.
> 
> More light gives algae a chance to take over, so fast-growing stem plants will help utilize nutrients in the water to keep this from happening.


Well, I can understand that getting normal light fixtures are good. Although are the light bulbs you buy at the hardware store... ect good enough for the plants? like the photosynthesis cycle and all.


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## budcarlson (Feb 3, 2009)

You need a trichromatic or full spectrum bulb. Standard bulbs will not do, they generally cover only 2 spectrums. Usually these bulbs will say 'natural light' or 'full spectrum' but not always, and 'natural light' or 'daylight' doesn't necessarily mean full spectrum.

Update on the WPG rule: this is a real good read if you have the time to understand why the WPG rule is realistically outdated.

Updating the WPG rule (theory) - Aquarium Advice - Aquarium Forum Community

And the calculator program to go with the evolving theory:

New Lights?

I was at 30W full spectrum T8 lighting 5500K and was getting growth from some plants, none from others. I got a $17 shop fixture from Menards and put 2 4' 32W T8s from home depot ($7.50 each) and that upped it to 64W of T8 lighting, which is effectively 90W of equivalent T12 lighting, so I'm right around the old 2 'WPG' and my plants are doing much better. I also got new glass from the hardware store ($12) for the lid to match the width of the light, my old ones had a lot of calcium built up on them. I can already tell a big difference, plus the tank looks nicer.


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