1. Please double check and update your email --> http://www.monsterfishkeepers.com/forums/index.php?account/contact-details
    Dismiss Notice

Lighting a Planted Tank

Discussion in 'Planted Tank and Aquascaping' started by WyldFya, Jun 5, 2007.

  1. WyldFya

    WyldFya
    Expand Collapse
    Baryancistrus demantoides
    Staff Member

    Real Name:
    Joined:
    Dec 23, 2005
    Messages:
    20,765
    Likes Received:
    3
    Trophy Points:
    89
    Occupation:
    University HPERD instructor, Pet store employee
    Location:
    Moscow, ID
    Last Seen:
    Today at 9:53 AM
    By: ErrorS at www.AquariaCentral.com

    I want to get rid of watts per gallon, I'm sick of it. It just plain doesn't work anymore.. MHs can be anywhere from 70 to 110 lumens per watt, incandescents and halogens can be from 10-20lumens per watt and Fluorescents (HO, VHO, NO) can be anywhere from 45 to 130 lumens per watt. That's a huge range.. just in commonly used bulbs for aquariums you can go from 70 to 130 lumens per watt.

    It's horrible.. I could tell you I had 6WPG of VHOs on my tank, which sounds really really high, but it's only outputting the light of 3WPG of normal output fluorescents.

    It's simple enough..

    just lumens divided tank (depth*2) + tank width + tank length. It's very simple, based on lumens per gallon except it stresses the tank height more.

    In other words.. you multiply the depth times two, then you add this number to the width and length and divide the lumens with it.

    So for 10K lumen output on a 55G tank it would be: 21*2 (42).. 42+12+48 (which would be 102), then you divide 10,000 by 102 to get the value you need.

    Below 50 is very low lighting - (fish only)
    50-150 is low to moderate lighting - (Fish only or lower-light plants)
    150-250 is moderate to high lighting - (typical planted tanks without CO2)
    250-350 is high to very high lighting - (Good reef tanks or heavily planted)
    350-450 is very high to extreme lighting - (the best reef tanks or extremely high light plants)

    This is for 10k Lumens, about two 55W power compacts.

    72x25x25 - 180G-(tank is 147) - 68
    48x24x21 - 75G - (tank is 114) - 87
    48x12x21 - 55G - (tank is 102) - 98
    30x12x30 - 46G - (tank is 102) - 98
    30x12x12 - 20G - (tank is 066) - 155
    30x12x18 - 29G - (tank is 078) - 128

    As you can see, the 46G, even though it has less volume requires just as much lighting as a 55G.

    Now, if it was 20k lumens which is a good value for a 55/75 moderately planted aquarium (This is about two 175W MHs average.. or a bit less than four T5 HOs), you wuold have these numbers.

    20K lumens is about what people seem to shoot for in a 20L reef and you can just get by with this amount in a 29G reef.

    72x25x25 - 180G-(tank is 147) - 136
    48x24x21 - 75G - (tank is 114) - 175
    48x12x21 - 55G - (tank is 102) - 196
    30x12x30 - 46G - (tank is 102) - 196
    30x12x12 - 20G - (tank is 066) - 303
    30x12x18 - 29G - (tank is 078) - 256

    Most bulbs vary only a small amount in lumen output.. even full spectrum bulbs, for the 5000-6000lumen bulbs (T5 HOs) it's only a matter of 500 or so lumens lost to get some of the invisible spectrums for your plants, which doesn't mess up the values above..

    or the equivilent of one 48'' bulb or one of those 40W screw-in CF bulbs, about 3000 lumens.

    72x25x25 - 180G-(tank is 147) - 20
    48x24x21 - 75G - (tank is 114) - 26
    48x12x21 - 55G - (tank is 102) - 29
    30x12x30 - 46G - (tank is 102) - 29
    30x12x18 - 29G - (tank is 078) - 38
    30x12x12 - 20G - (tank is 066) - 45
    24x12x12 - 10G - (tank is 060) - 50.. and as you know, one screw in CF is about enough for low light plants in a 10G, most people fit two, which would simply double this number making it 100...
     
  2. WyldFya

    WyldFya
    Expand Collapse
    Baryancistrus demantoides
    Staff Member

    Real Name:
    Joined:
    Dec 23, 2005
    Messages:
    20,765
    Likes Received:
    3
    Trophy Points:
    89
    Occupation:
    University HPERD instructor, Pet store employee
    Location:
    Moscow, ID
    Last Seen:
    Today at 9:53 AM
    For clarification, when you see 10K lumens, this refers to 10,000. K standing for kilo or thousands.
     
  3. jcardona1

    jcardona1
    Expand Collapse
    MFK Members

    Real Name:
    Jose
    Joined:
    Jun 5, 2007
    Messages:
    11,493
    Likes Received:
    9
    Trophy Points:
    0
    Occupation:
    SOX Compliance Auditor
    Location:
    South of Heaven
    Last Seen:
    Feb 25, 2013
    Ok, so we all know the watts per gallon (wpg) rule is pretty much useless these days with all the different types of lighting. there are other ways using lumen calculation but i still dont like this, and is usually pretty damn confusing.

    a member on plantedtank.net put together a great chart, using real data gathered with different bulbs and a PAR meter. this is awesome, and is a great reference for seeing what catergory of light youre in when it comes to plants. or how many bulbs you'll need to be in a certain category.

    NEWPARVSDIST.jpg

    example, let's assume that i have a standard 55g tank(48x15x18). now, with a height of 18", let's say our light fixture will be 18" away from the bottom of the tank after taking into account your substrate depth of approx 2".

    so based on this chart, if i were to run one T5HO bulb (assuming the bulb spans the length of the tank), this bulb would give me 65 micromols of PAR, which puts me in the MEDIUM light category. now if my fixture had two T5HO bulbs, just multiply the figure by 2, which gives us 130 micromols of PAR and well exceeds what is considered HIGH light. this may be too much lighting and could potentially give you algae problems. easy enought right??? :D

    same scenario, but let's assume we're using a standard T12 bulb. that gives us 10 micromols of PAR per bulb, which isnt even considered low light. we'd need 3-4 bulbs to be in the low light category. wanna be "high" light with T12 bulbs? gonna need at least 8 friggin bulbs!!!

    now you see why T5HO are the most effecient and economical choice when it comes to lighting, especially for planted tanks.

    so what do you guys think? can we put an end to all those wpg rules? i think this is easy enough, and should be a good guide for those wondering about lighting. afterall, the hardcore planted tank freaks ignored the wpg rule a long time ago!!! :)



    here's the original quote, and full thread:

    http://www.plantedtank.net/forums/lighting/105774-par-vs-distance-t5-t12-pc.html

     
    Collapse Signature Expand Signature
  4. pjsmetana

    pjsmetana
    Expand Collapse
    MFK Members

    Real Name:
    Pete
    Joined:
    Apr 26, 2010
    Messages:
    564
    Likes Received:
    0
    Trophy Points:
    0
    Occupation:
    pR0n STAR!
    Location:
    Cocoa Beach, FL
    Last Seen:
    Jul 26, 2012
    Great... so @ 30" I'm pretty much at "low light" no matter what?
     
    Collapse Signature Expand Signature
  5. jcardona1

    jcardona1
    Expand Collapse
    MFK Members

    Real Name:
    Jose
    Joined:
    Jun 5, 2007
    Messages:
    11,493
    Likes Received:
    9
    Trophy Points:
    0
    Occupation:
    SOX Compliance Auditor
    Location:
    South of Heaven
    Last Seen:
    Feb 25, 2013
    not really, the data in this chart is when using ONE bulb only. at 30", a T5HO bulb gives you close to 30 micromols of PAR. the highlight category starts at 80, so use three bulbs and youre at 90 (30 x 3) :)
     
    Collapse Signature Expand Signature
  6. Pharaoh

    Pharaoh
    Expand Collapse
    Administrator

    Real Name:
    Bobby
    Joined:
    Feb 18, 2008
    Messages:
    17,478
    Likes Received:
    47
    Trophy Points:
    1,052
    Occupation:
    DIY'er
    Location:
    Indianapolis
    Home Page:
    Last Seen:
    Today at 1:08 PM
    based on this, my four bulb PC light is at roughly 112. I think that's a bit off. I wouldn't dream of being able to run a high light tank of my setup. I could be wrong though.
     
    Collapse Signature Expand Signature
  7. jcardona1

    jcardona1
    Expand Collapse
    MFK Members

    Real Name:
    Jose
    Joined:
    Jun 5, 2007
    Messages:
    11,493
    Likes Received:
    9
    Trophy Points:
    0
    Occupation:
    SOX Compliance Auditor
    Location:
    South of Heaven
    Last Seen:
    Feb 25, 2013
    do the bulbs span the whole length of the tank? if so, then the data is correct. the PAR meter doesnt lie. the meter simply measures the intensity of light at the bottom of the tank, regardless of type of bulb, watts, kelvin rating, etc. a good reflector does make a huge difference though...
     
    Collapse Signature Expand Signature
  8. dxdx

    dxdx
    Expand Collapse
    MFK Members

    Real Name:
    Joined:
    Jan 26, 2010
    Messages:
    1,110
    Likes Received:
    1
    Trophy Points:
    38
    Location:
    NJ, USA
    Last Seen:
    Aug 12, 2015
    Maybe I'm missing something - it's late in the workday. But, what wattage is the green line? My 18 watt T5HO bulb produces 100 micromols of PAR at 14 inches?
     
  9. Pharaoh

    Pharaoh
    Expand Collapse
    Administrator

    Real Name:
    Bobby
    Joined:
    Feb 18, 2008
    Messages:
    17,478
    Likes Received:
    47
    Trophy Points:
    1,052
    Occupation:
    DIY'er
    Location:
    Indianapolis
    Home Page:
    Last Seen:
    Today at 1:08 PM
    I might have to calculate mine a bit differently as I have four bulbs at 22" each. Two on each side of the aquarium. I'm thinking I should calculate it as two bulbs that run the length of the aquarium.
     
    Collapse Signature Expand Signature
  10. jcardona1

    jcardona1
    Expand Collapse
    MFK Members

    Real Name:
    Jose
    Joined:
    Jun 5, 2007
    Messages:
    11,493
    Likes Received:
    9
    Trophy Points:
    0
    Occupation:
    SOX Compliance Auditor
    Location:
    South of Heaven
    Last Seen:
    Feb 25, 2013
    wattage is not really important here. this is measuring light intensity at the bottom of the tank using a PAR meter. so yes, at 14" from the bottom a T5HO bulb gives you approzimately 91 micromols of PAR (didnt look like 100 to me).

    it's also important to note that the bulb must span the WHOLE length of the tank, otherwise youll have less light at the edges of the tank. the thing to remember is that height is very important when determining light intensity
     
    Collapse Signature Expand Signature

Share This Page