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The high light requirement myth

Discussion in 'Lighting' started by Gerryd, Jul 18, 2010.

  1. Gerryd

    Gerryd Plant Guru Team
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    Hi all,

    I have a Current Outer Orbit MH 3x150 watt 6500k fixture.

    It is mounted 31.5" ABOVE the tank to provide a surface PAR of around 100 or so and about 50 max at the substrate.

    The fixture came with mounting legs that would place the lenses maybe 2-3" above the water surface.

    I placed my remote PAR sensor in a container of water and lifted the container to within several inches of a lens.

    The PAR readings were as follows:

    3" from lens: >1500!
    3-4" from lens: 1100-1300!

    So, if someone were to actually use this light and mount it as directed, they would NEVER IMO be able to supply enough c02 and I have to think the tank would have multiple algal and growth issues..

    The hobbyist would be at a huge disadvantage right from the start...even if flow and c02 was 'optimally' setup for their tank size, they would be fighting a losing battle...

    Tom has mentioned that >150 PAR starts to be higher light territory... If so, what is 10 X that amount??

    So, again it makes me think of how much light we are giving our tanks, and are we all maybe starting off with an imbalance on the higher light side...

    If we used WPG here, it would be 450 watts divided by 180 gallons = 2.5 WPG.

    Okay fine, that may be considered high light, but I doubt that anyone has any clear idea of just how much light that 2.5 wpg really is....how would you ever meet c02 for that??

    When the lights were just at 24" above the surface the PAR values were doubled the current values..so 100 at substrate and 200> at surface.. High light for sure

    Would anyone think that to make this a 'low light' tank to raise the fixture that high w/o a meter? I could just about stick the fixture to the ceiling it is so close....

    Is the recommendation anywhere near 24" above the tank for MH fixtures? Certainly not 61 cm!!!! and that just brings us DOWN to a high light tank!! who would ever think 78 cm to get to low light? I don't think many....

    I really see now with the meter just how ridiculous are the amounts of light we give our tanks.

    Granted, MH are used for corals, but still many folks such as myself use them for freshwater....

    I was fortunate enough to never use these mounting legs, but when I think that at the start they were raised maybe 10-12"......no wonder I used to have so many issues trying to meet c02 demand.....

    Daily I read threads from folks who think that 4x39w of T5 is NOT ENOUGH for a 75 gal tank....I NEED it for red plants, or HC....

    I am now joining Tom as an official advocate of the LOW light brigade...

    Appreciate any thoughts or comments..
     
    #1 Gerryd, Jul 18, 2010
    Last edited by a moderator: Jul 18, 2010
  2. ibanezfrelon

    ibanezfrelon Guru Class Expert

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    Very useful text Gerry!
    Just yesterday a guy asked for help on my local forum , his plants were falling apart ,he had Rio 180 (180 lit)just like me only very poor flow and very low co2...
    ...he was pps dosing... ..and the best thing is - he added extra 2x45w t5's!!!!!!! ...meaning overall 4x45w of t5 mounted 1 inch above water!!!!
    Everyone was saying to him nitrates this and phosphates that while i was trying to explain to him that co2 is nr1 problem..
    I think that Wpg measurment is one of the biggest cause of co2 issues in tanks today , and it doesn't help that co2 issues are recognised as nutrient issues etc...

    Ithink this kind of tests are eyeopeners , i would certanly like to see more of them..
    ..or maybe even a Par calculator or something in the future..
     
  3. Tom Barr

    Tom Barr Founder
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    It's called actually testing your light to have comparative means to measure light tank to tank.
    For all the wind bags and know nothings out on forums, I find it incredulous when they criticize EI so much then guess entirely with light.

    Does the right hand know not what the left is doing?

    I tested before I took the leap or faith and also have math on my side.
    They ain't got nothing.

    Pure guess.

    "Mean old Tom does not know nuthing...."

    Regards,
    Mean Old Tom Barr

    hehe
     
  4. CL_

    CL_ Guest

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    Hahaha! Too funny!
     
  5. dutchy

    dutchy Plant Guru Team
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    hahaha better late than never....;)

    Anyway I think it's good that you posted this, another experience for others to read.

    regards,
    dutchy
     
  6. SuperColey1

    SuperColey1 Guru Class Expert

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    Welcome to the club Gerryd. Welcome to the teenies :) High light is so noughties (and the couple of decades preceeding). lol

    A little strong. lol. Any rule is only as good as those who use and suggest how to administer it. I think the WPG rule is OK as long as you understand it only applies to T12 lighting and for other flourescents it needs 'adjusting'. It definately doesn't apply to Gerryd's MH 'lighthouse'. However if Gerryd can confirm no ships have crashed into his house then the lighthouse has done it's job. lol

    Never blame the rule, blame the administrar
    AC
     
    #6 SuperColey1, Jul 19, 2010
    Last edited by a moderator: Jul 19, 2010
  7. Tom Barr

    Tom Barr Founder
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    With good CO2, you can make most lighting systems work well.
    I went that route for a long time. Still do......... but put the light data into all this to complete the management picture.
    Also, experience helps a lot.

    Still, knowing specifically what is going on with light, in other words, comparing our suspicions........that's more powerful.
    Then we have a much better idea.

    Now things make more sense and I do not need to buy every sort of light system on the market, just a pesky 200-300$ light meter!! ahaha

    Regards,
    Tom Barr
     
  8. Gerryd

    Gerryd Plant Guru Team
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    Hi all,

    Please note that I am already a low light advocate FOR OTHERS :) Just did not apply it to myself...

    I did know what my PAR was but was too lazy to remount the lights higher and figured I could deal with it...ha ha ha...that's a good one....

    Now that I AM in lower light territory it got me curious what the PAR may have been when I first started out..and was over the years..

    So, combine my 'lighthouse' with a novice user of c02. Think they would eventually give up and think c02 didn't help when all their issues were way too much light in the first place?

    I spent $1,000 on that MH fixture and most likely could have just kept my 240watts of T12 instead....would most likely have given me my DESIRED PAR!!!!

    I could have spent that $ on lots of other stuff and had years of trouble free maintenance...well maybe lol

    I just want others to avoid my same mistakes....
     
  9. shoggoth43

    shoggoth43 Lifetime Charter Member
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    Well, if you don't know any better at the time, how are you going to find out?

    Also, 2-300$ for a PAR meter aint exactly cheap when a decent Tek5 goes for around that depending on what you buy. And if Amano's lights are all mega wattage in the magazines, well then what is anyone supposed to think? ( Yes, we know his reflectors are crap and the lights are really inefficient so his PAR is a reasonable amount )

    I gave the site URL to someone at the LFS on Saturday. He had a 150 and already had decent lighting, but the guy at the store was suggesting some PC supplemental lighting to "punch" down to the bottom of the tank. He said he had CO2 but I got the feeling he might not use it this time. Hopefully he's lurking around her somewhere learning some of this before he has an algae tank with some fish in it.

    -
    S

     
  10. SuperColey1

    SuperColey1 Guru Class Expert

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    Lol. I am in that club too. Many of us are. My setup cost me in the region of £1500+ over the initial trials and upgrades. I dare say I could make it from scratch for £500 or so now. lol

    Its great to learn but costs a lot. he, he.

    ........Oh and I too had a 'lighthouse' at one stage :p

    AC
     
  11. Tom Barr

    Tom Barr Founder
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    So... go forth and covert thy masses. Speak of woe and ill, and show them the light needth not be as bright to see the Promised Land.
    The land of nice growth and fishys is not as far away as many think.

    Yes, all those rules do not apply to us, just other folks.
    Right!!!



    Regards,
    Tom Barr
     
  12. Gerryd

    Gerryd Plant Guru Team
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    Hi Tom,

    I am onboard and good to go here.....I want to bring my meter to the LFS and see if they are even interested in it...should be interesting..

    Hopefully will not need to become a desert hermit/prophet to do so :)

    Whom are you meaning here??? Folks who won't test light buy tell you EI is wrong?? Sorry, I lost the context...

    Thanks
     
  13. I Love Aqautic Weeds!

    I Love Aqautic Weeds! Prolific Poster

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    I would just like to second all this talk of low light.

    I lowered my 46 Bowfront WAY down to .9 watts (down from 1.8) of T-5 sitting 1-2 inches off the surface and the difference has been dramatic to say the least. Algae of all kinds is declining, BBA rapidly, GSA more slowly. And growth is faster and much lusher under the lower light!

    Tom, are you going to write a book or what?!?!? Your thoughts and know-how can and most certainly will turn the planted aquarium hobby on its head hand help thousands of hobbyists. I will buy your book.
     
    #13 I Love Aqautic Weeds!, Jul 20, 2010
    Last edited by a moderator: Jul 20, 2010
  14. Gerryd

    Gerryd Plant Guru Team
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    Hi,

    I am not surprised that things are better after reducing your light...glad to hear your doing well with it as well...
     
  15. hbosman

    hbosman Guru Class Expert

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    I run a 46 Gallon BF and used to use 4x39 watt T5HO lighting for 9 hours. BBA and GSA were always present to some degree. Through advise from Tom and others, I reduced my lighting to 2x39 watt bulbs for 9 hours and my BBA has reduced as well. I even swapped out my Giesmann bulbs for Current 6500 K bulbs to reduce PAR. The next thing I did was go from a Boyu inline defuser back to a powerhead with the split and bend impeller modification. Although I'm not fond of the mist all over the place look, I do like the improvement in growth and reduced GSA and BBA algae. I also went to using one timer for lights and CO2 from three timers. As far as I can see, I don't need to start CO2 prior to lights turning on. Probably, because my drop checker is still green in the morning. That surprised me since I do have decent surface ripple.

    Anyway, I just wanted to express my delight at this much simplified method of algae reduction and still having great plant growth. My Rotala Macandra isn't the reddest I've ever seen but still the same color it was under 156 watts of light.
     
  16. shoggoth43

    shoggoth43 Lifetime Charter Member
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    156 Watts of T5HO? WOW! I'm guessing you're so much happier now. Your electric bill probably thanks you too.

    And I thought I was bad when I had 160 Watts of T12NO over my 75 gallon way back when.... :)

    -
    S
     
    #16 shoggoth43, Jul 21, 2010
    Last edited by a moderator: Jul 21, 2010
  17. hbosman

    hbosman Guru Class Expert

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    With two teenage kids, I probably won't notice a change in the electric bill. : - )
     
  18. Tom Barr

    Tom Barr Founder
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    And this is why they need paying jobs.

    B's and A,s, school sports, music etc, no rest for the wicked, money don't grow on trees.
    Crack the whip. Adapt as they change(harder for the parent than the teenager!!!).

    No nagging them if they do the above.
    That's the deal.
    They hate the nag.



    Regards,
    Tom Barr
     
  19. Tug

    Tug Lifetime Charter Member
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    I think Tom's witticism is meant to be dry sarcasm. Even Paul the Apostle was blinded by the light before he saw the error of his ways.
     
  20. Tom Barr

    Tom Barr Founder
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    Sarcasm is harder to convey on the web.

    I try to refrain, but it comes out here and there.

    Regards,
    Tom Barr
     
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