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Thread: The high light requirement myth

  1. #1
    Join Date
    Sep 2007
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    South Florida
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    The high light requirement myth

    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..
    Last edited by Gerryd; 07-19-2010 at 02:16 AM.
    Thanks,

    Gerry.

    'When something's not right, it's wrong'. Bob Dylan

    Current 220 scape

    http://www.barrreport.com/showthread...3219-220-video

  2. #2
    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. #3
    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. #4
    CL_ Guest
    Quote Originally Posted by Tom Barr View Post
    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
    Hahaha! Too funny!

  5. #5
    Join Date
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    The Netherlands
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    Quote Originally Posted by Gerryd View Post

    I am now joining Tom as an official advocate of the LOW light brigade...
    hahaha better late than never....

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

    regards,
    dutchy
    regards,
    dutchy.

    My 2011, 2012 and 2013 AGA aquascaping contest entries:
    http://www.barrreport.com/album.php?u=21013

  6. #6
    Welcome to the club Gerryd. Welcome to the teenies High light is so noughties (and the couple of decades preceeding). lol

    I think that Wpg measurement is one of the biggest cause of co2 issues in tanks today
    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
    Last edited by SuperColey1; 07-19-2010 at 01:24 PM.

  7. #7
    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. #8
    Join Date
    Sep 2007
    Location
    South Florida
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    5,597
    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....
    Thanks,

    Gerry.

    'When something's not right, it's wrong'. Bob Dylan

    Current 220 scape

    http://www.barrreport.com/showthread...3219-220-video

  9. #9
    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

    Quote Originally Posted by Gerryd View Post
    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....

  10. #10
    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
    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

    AC

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