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Aquariums, Plants, and Lights

  1. Nov 18, 2007 #1
    Hi all, I was hoping someone more knowledgeable about aquariums and specifically aquarium plants could help me out here. I have a 10 gallon aquarium that has two incandescent bulbs in the hood. I went to the pet store to get a plant for it, and they tell me that I should get one of those (14W) fluorescent tubes instead. Unfortunately to do that, I would need a new top for my aquarium, something like 80 bucks. They also had http://www.exo-terra.com/en/products/compact_fluorescent_bulbs.php" [Broken], which (2) will fit into my current top (at least, the 13W ones will). I asked them if one of them would work, and they said no, something about the light not reaching the bottom of the tank. I know that that's nonsense, there's no way that the light will not travel through the foot or so of water to the bottom of the tank.

    My question is, is there any other reason why these bulbs wouldn't work for my fish and a plant as well? Should I get one or two? And which kinds? They have the 2.0, 5.0, and 10.0 (I think the numbers are based on the %age of UV light). Should I get 2 different ones? Or 2 the same?

    Thanks in advance.
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Nov 18, 2007 #2


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    When you said "these bulbs" I looked and it described bulbs for reptiles not fish. There's a difference I assume in what lightbulbs to use for fish and what to use for the amphibians since reptiles need to basically keep their body temperature up.

    Fluorescent bulbs work pretty well I assume since I've seen them being used at the petshop around here.

    I did use a bulb with a aquarium cover over one of my tanks since it was below the other tank and it used 2 normal 25 watt aquarium bulbs. I decided not to use it however since it was a normal bulb and it used alot of electricity. If you want to have plants that should be fine to use either a normal bulb or a fluorescent bulb but I'm not so sure about the bulbs from the link you gave since keep in mind it looks like a energy save bulb and if it is then it'll probably go dim in a few months thus the plants will get less light and you'd have to buy another one.

    My tank that had the light was a 10 gallon tank. Mine kept the tank nice and bright but I don't prefer to keep plants. (they dirty the aquarium and then you'd have to have some gravel and then the waste of the fish gets into that and so on...)
    I keep the bottom bare in my tank.

    Technically if there is a bulb that says "aquarium bulb" and if the size fits in the hood that you use for your aquarium it should do fine. (I used a 25 watt bulb)
    The ones I had were about 4 inches long.

    You also could search online for info on aquarium bulbs (not amphibian bulbs).

    Mine looked like this http://www.aquariumguys.com/crystalux.html

    Also after reading that website which I just linked apparently the incandecent bulb gives off alot of heat. Due to that I could safely say thaty you'd probably wouldn't want a floating plant to be under that light thus that's probably why they told you to get a lower watt bulb. However if the plant you want to get will not be near the surface of the water (within a inch or two) it should be fine to stick with a 25 watt incandescent bulb.
    Last edited: Nov 18, 2007
  4. Nov 18, 2007 #3
    The bulbs that I linked to are fluorescent bulbs, but the screw in kind (not the straight tube). The frequencies that it gives off are a little different from the tube one they were trying to sell me, but spectrum doesn't look that much different. But if I want the tube one then I need to by a whole new top for my tank, which I'd prefer not to do. I was hoping someone would be able to tell me for sure if there was something in the spectrum that those ones put off that would make them unsuitable for my aquarium.
  5. Nov 18, 2007 #4


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    It's not nonsense. Certain wavelengths will only penetrate so far. It's dependent on the tank size and wattage. Those cfs likely won't be enough unless you put more than one in.

    Halogens are best for reaching to the bottom of the tank, but they're hot and expensive.

    BTW, most smaller store-bought tanks are severely under-equipped for lighting.

    Something waay in the back of my mind says that the rule of thumb for plant lighting is 5W per gallon.
  6. Nov 18, 2007 #5
    Yeah, but if I remember my E&M, then the visible spectrum will penetrate water to quite a depth, definitely more than a foot or two, with little attenuation.
  7. Nov 19, 2007 #6


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    Your lighting system is often the most expensive piece of your aquarium - more than your tank. If you wish to grow plants, you should invest in it. Otherwise, you'll constantly be fighting to keep your plants alive.

    Here's a littel blurb that talks about it:
    http://en.allexperts.com/q/Freshwater-Aquarium-3216/Plants-1.htm [Broken]
    Last edited by a moderator: May 3, 2017
  8. Nov 19, 2007 #7
    Ok, so the 14 watt tube and hood that they were trying to sell me would be just as useless for growing plants as the two 13 watt bulbs I was looking at, if not more so. I will look more into the articles they recommend about making your own lighting kits.

  9. Nov 19, 2007 #8
    Be sure to keep the lighting time limited to 11-12 hours, which it is natural in the tropics. If you switch on lights at earliest time in the morning and off when closing for the day then expect the algae to take over completely.

    The best suitable water plants for a low light situation that I know off are Java moss (Vesicularia dubyana) and Java fern (Microsorium pteropus). No need for gravel as well, just a stone or a piece of peat wood to attach the roots.
  10. Nov 19, 2007 #9


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    Certainly. IMO, a timer is a critical piece of equipment. For $10 it's not an expensive one. 10-12 hours is about right - YMMV, depending on how much you like cleaning algae.
  11. Nov 19, 2007 #10
    I will try to find a timer for mine, and see what I can't rig up for a lighting scheme. I might just see if I can adjust (or change) the lighting fixture inside the current hood to fit other bulbs.
  12. Nov 19, 2007 #11
    My research elsewhere on the internet seems to suggest that for low light plants one should have between 1-2 W/Gallon, while for plants with a medium light requirement will need anywhere from 1.5-3.5. Though anything above 2 and you might need CO2.
  13. Nov 19, 2007 #12


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    Low light plants? Not familiar with that.

    IME, all planted tanks always require more light than the average light usually provided for in a non-planted tank.
  14. Nov 19, 2007 #13
    Relatively low light requiring, yeah, that's still more than in a non-planted tank.
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