This site is supported by the advertisements on it, please disable your AdBlocker so we can continue to provide you with the quality content you expect.
  1. We are after as many aquarium plant images that we can get, doing so will assist us in completing the aquarium plant database.

    https://barrreport.com/threads/aquatic-plant-images-wanted.14374/
    Dismiss Notice

PAR at 0.8W/gal- or we really do not need much light

Discussion in 'Lighting' started by Tom Barr, Nov 12, 2010.

  1. SuperColey1

    SuperColey1 Guru Class Expert

    Joined:
    Feb 17, 2007
    Messages:
    503
    Likes Received:
    0
    Local Time:
    8:40 AM
    Bsmith - I'm not trying to pick apart other people's statements.

    The 'it has long been understood' statements are pretty meaningless IMO, after all lots of 'long been understood' theories have been blown out of the water.

    For example a few years ago people would have said 'it has long been understood we ned 3WPG+' etc.

    I was just trying to point out that when you changed from the highlight to the lowlight, you also reduced the available CO2 and ferts therefore it could be any of those 3 factors or a combination of them rather than just asume it was the light.

    For example HC grows very well and compact under what would be considered low light. Most people will say howwever that 'it has long been understood' that HC is a high light demanding plant. I would argue it is high CO2 plant. Can still be grown compact in a Non CO2 setup though if the substrate is suitable i.e. producing CO2.

    AC
     
  2. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,691
    Likes Received:
    711
    Local Time:
    8:40 AM
  3. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,691
    Likes Received:
    711
    Local Time:
    8:40 AM
    HC can be grown in a non CO2 tank, I've seen a few examples.

    Regards,
    Tom Barr
     
  4. bsmith782

    bsmith782 Guru Class Expert

    Joined:
    Mar 14, 2007
    Messages:
    147
    Likes Received:
    0
    Local Time:
    8:40 AM
    Again I dont want to argue but your post is very contradictory. You stated, "I'm not trying to pick apart other people's statements" then right under that you posted your argument about HC. I never brought up HC. So you threw in something I said nothing about to try to solidify your view which has nothing to do with what I said.

    The argument about HC's preferred habitat is one that many go back and forth about and it a regular issue for debate. However the fact that plants grow longer and tend to grow towards a light source is not. It is fact.

    This is why I posted in my first post that My tropica 049 grew much taller and not compact. I could breakdown all of the variables (light co2 and fertilazation) and ill bet that light comes up as the reason behind this. :)
     
  5. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,691
    Likes Received:
    711
    Local Time:
    8:40 AM
    I saw Starougyne growing in Erik Olsen(of theKrib.com) without CO2 very compact.

    You have to be careful saying X causes Y.
    All it takes is 1-2 examples to disprove that.
    It grew much slower, but it looked pretty good and growth was compact.

    He has some 20-30 tanks and it's a neglected tank with old flourite.

    I did not measure the light, it was higher if I where to guess, but.......it would be nothing more than guess.

    HC as well.

    A simple light test that makes CO2 truly independent: emergent growth with a good sediment and then VARY THE INTENSITY.
    Or crank the bejesus out of the CO2 etc without any livestock.

    Can you measure noticeable differences in the internodal spacing?

    I've not noticed any.
    Longer when submersed, but this could be due to CO2 and carbon conservation.


    Regards,
    Tom Barr
     
  6. pat w

    pat w Member

    Joined:
    Nov 4, 2009
    Messages:
    462
    Likes Received:
    0
    Local Time:
    8:40 AM
    May have an observation that could throw a monkey wrench into your statement.

    While I was bringing my system online and my CO2 levels were below what they needed to be I had stems that were leggy, seemed to run straight for the surface, and didn't send off any side shoots to speak of. Once I got my CO2 running at an acceptable rate the opposite seem to be the case. The long growth gave way to lower growth with more side shoots and closer node spacings. The upward growth is toward the light but also toward the surface where the CO2 "normally" is, so it's hard to say that vertical growth is only dependant on the drive toward a light source.

    Pat
     
  7. Ekrindul

    Ekrindul Guru Class Expert

    Joined:
    Jul 9, 2010
    Messages:
    114
    Likes Received:
    0
    Local Time:
    8:40 AM
    I haven't noticed this in observing my own plants. I've been much more successful in achieving compact growth by controlling flow (which in turn controls fertz and CO2 distribution) to areas of the tank. If I remove the flow to another part of the tank, I see leggier growth in the area of descreased flow within a week. If I return the flow, within a week I see compact growth resume. The most logical assumption, whether it's right or not, would be CO2 levels.
     
  8. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,691
    Likes Received:
    711
    Local Time:
    8:40 AM
    Good point on Flow also.............
    Obviously, flow will effect the direction of plant growth, more current in general= more compact growth for many species.

    In rivers, some plants might have to grow 30ft to make it to the surface in 8 ft of water.

    Plants have to invest more in stronger stems in higher current, otherwise the stems would break off.

    Autofragmentation is common when CO2 stress is strong or there is a sudden change.
    This way a piece of the plants will drift off, much like seeds.......to hopefully a better environment.


    Still, this thread is mostly about light, not stretching.
    The point is really that it's much less than I could have guessed.




    Regards,
    Tom Barr
     
  9. SuperColey1

    SuperColey1 Guru Class Expert

    Joined:
    Feb 17, 2007
    Messages:
    503
    Likes Received:
    0
    Local Time:
    8:40 AM
    Indeed Tom. I think with CO2 addition you could get down to the 0.4 - 0.5WPG and have success with most plants. Slower but not as slow as a non CO2 tank with say...1WPG

    I personally think it could go lower still.

    Is the 0.8WPG what you would suggest is the lowest to grow any plant at a reasonable growth rate?

    Its a pity the manufacturers are way behind those who do real life observations. In europe all the brand names have increased their stock lighting in their canopies to double T5HO where 3-4 years ago they were just double T8s.

    That of course means those who believe(d) the highlight myth would now not need to upgrade their lighting. As it happens Newbies are now having huge problems when they start planted (with these brand name tanks) and I and others are telling them they need to downgrade. lol

    Maybe they will return to lower lighting in 3-4 years time and go full circle. lol

    AC
     
  10. dutchy

    dutchy Plant Guru Team
    Lifetime Member

    Joined:
    Jul 6, 2009
    Messages:
    2,280
    Likes Received:
    4
    Local Time:
    8:40 AM
    Something that could play a role is.....time. If a plant would take months to reach a respectable length, maybe it will lose the lower leaves just because of age. Some plants will turn into palm trees, while with more light, the plant grows faster and doesn"t have the time to lose the leaves.

    Also the decrease in light could make plants lose the leaves just because of lack of light.

    I can see this with my Aromatica's. When the plants are 20 inch tall, at 90 micromols they have around 4 inch of bare stem. At 55 micromol, they have 10 inch of bare stem. The same difference doubles the internode distance on the Stellata's, although the leaf length an width increases by 50% at low light. Maybe this is the plants compensation to catch light more effectively or the plant is less limited in CO2. Not sure about that.

    As long as your able to provide enough CO2 and are happy with the speed of growth, there's no real need to "how low can you go". Also the esthetic effect plays a role here. Fish like cardinals colour much nicer with more light, but also red plants look brighter and more "fresh".

    I'm not happy to look at my tank with 25 - 30 mmol. Everything looks kind of dim....

    regards,
    dutchy
     
  11. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,691
    Likes Received:
    711
    Local Time:
    8:40 AM
    I think you are correct, and with better more efficient light, we may see this.
    Many in the PPS dosing crowd liked to argue that less is better ecologically when it comes to fertilizer, but went the entire opposite direction when it came to light.
    I did not find this to least bit logical if you go with that "ecological philosophy" argument.

    I think as you get down lower and lower with light, the elevation of the gravel slopes will make larger/more significant differences.
    You also have plant species differences becoming more and more significant. Most will argue that java fern or moss will handle less light than say some stem plants and still look presentable for aquascaping.
    Spread of the light may also begin to make a much large significant difference as folks try less and less light.

    As you can see/might predict, as we get lower and lower, there's less room for error.

    I think the main goal of EI is to provide ample dosing easily, with adding just enough ferts to provide non limiting growth from the ferts.
    It is not, and never was, about gross waste as some have long suggested. Likewise, what is a good range for light?
    Well, depends on CO2 a lot as well.

    Good CO2= less light required.

    So I think it's easy to get around nutrients, but a little more troublesome for CO2, but still possible.
    All in all, growth is typically limited by light intensity in most aquariums, regardless of the higher ranges........but it's a bear to manage in such systems.

    So we still limit growth mostly by light in virtually all aquariums.

    How much so is debtatable.
    How low can we go is also a big question.

    Theory and research suggest 12-20micromols I'd say, but that's without CO2 and good nutrients and for weeds.
    Questions remain.

    I do not think many will learn the utility of lower light, there are just too many folks who leave the web sites and do not update them or argue against high light.
    There are more folks these days that are arguing in favor or lower light.........many who use to be high light junkies and argued with me in the past about it as well.
    But.....the hobby as whle has a long way to go still.

    You are well off in the UK because things happened fast and cohesively there and there was always a good mentality about light to start with.
    USA? We can be idiots when it comes to overt consumption(Land of the Hummers and bigger is better).

    Regards,
    Tom Barr
     
  12. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,691
    Likes Received:
    711
    Local Time:
    8:40 AM
    I think here is an example of having ample buffering in light intensities.
    You can go lower, but the trade off is not as good horticulture and scaping.
    I can dose lower nutrients, but then I have issues, or dose lower CO2 and have other issues.
    Better to have a good range that is easy to manage and have some wiggle room.

    I think we also can say that these 2 stem plants will utilize the light and change morphology, leaf allocations(whether or not to drop or keep lower old leaves) far more than say Anubias barteri.
    There are likely large differences in species responses to light at the end points nearing the LCP(Light compensation point). Each species has it's own LCP's.

    Regards,
    Tom Barr
     
  13. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,691
    Likes Received:
    711
    Local Time:
    8:40 AM
    You also need to account for stem length/height and shading from other plants also.
    For the tank I'm planning here, I am using a shorter runner plant, dwarf corkscrew Val(tropica V. americana var biwaensis) in open areas.

    Keeping lower leaves on a plant that's pruned 10cm vs 25 cm long is much easier.

    Regards,
    Tom Barr
     
  14. dutchy

    dutchy Plant Guru Team
    Lifetime Member

    Joined:
    Jul 6, 2009
    Messages:
    2,280
    Likes Received:
    4
    Local Time:
    8:40 AM
    Of course, so it means there are trade offs. Each light intensity is dependent on tank height, the plants that we use and the scape and last but not least, if we can add enough CO2. This makes a statement about what the minimum is not valid.

    Also graphs that have been drawn about light intensities can fall short, depending on the goal of the aquarist. The only solution is looking with one eye to your PAR meter and the other eye to plant development.

    The problem is that we put all kind of plants together in one tank and expect all of them to grow without any problems. That works for the most part, but it's hard to get perfect.

    regards,
    dutchy
     
  15. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,691
    Likes Received:
    711
    Local Time:
    8:40 AM
    What is valid is under ideal conditions, so no CO2 limitation, no nutrient limitation etc and a single species.
    As we add more complexity......well..then things are harder to discern.
    I think going to the bone minimum is never good.........I prefer some wiggle room myself, but........for this tank.........30micromols is still not there.

    40-50 seems to work well for most tanks along the bottom.
    As a stem plant grows up towardss the light, the PAR also increases a good deal.
    So the tops might have 100-140 micromols.

    Regards,
    Tom Barr
     
  16. dutchy

    dutchy Plant Guru Team
    Lifetime Member

    Joined:
    Jul 6, 2009
    Messages:
    2,280
    Likes Received:
    4
    Local Time:
    8:40 AM
    This is a good average between growth, plant development and easy management. It's also possible to use short reflectors locally where plants need more light or need to grow in faster without increasing the light on the entire tank.

    What plants are you going to use besides the Vals?

    regards,
    dutchy
     
  17. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,691
    Likes Received:
    711
    Local Time:
    8:40 AM
    Just the super short vals, nothing else.


    Regards,
    Tom Barr
     
  18. Whiskey

    Whiskey Member

    Joined:
    Jun 14, 2010
    Messages:
    368
    Likes Received:
    1
    Local Time:
    8:40 AM
    I have an observation I can contribute to this thread.

    I have a 25G tall tank,.. it measures 24 by 12 by 24, so it's tall and narrow.
    It is lit by a single 18W NO and a single 55W PC in a really good parobolic reflector.

    For some time I had the PC lamp sitting about 12 inches off the surface in order to reduce the light and early tank algae issues; however about a month and a half ago I moved it down.

    Since moving the lamp closer to the water, I've noted faster growth, and much more red in one of my stem plants. The the Crypts and Anubis on the bottom also produce leaves faster and appear healthier. This aquarium has the dis-advantage of the taller plants shading out the lower ones due to how narrow it is, but in my case I think I went below your lower limit of light slightly with my inital setup. I think I had little enough light to adversely effect the plants on the bottom of my aquarium.

    I'm still working on finding a perfect balance, and I'm slowly winning the battle against some black algae on lower plants, but now that they are growing a little faster it's a huge help, and the algae has been slowly dissapearing.

    Whiskey
     
  19. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,691
    Likes Received:
    711
    Local Time:
    8:40 AM
    You may prefer that faster growth now........but you might change that view later, or you might leave for 1-2 weeks and need less growth etc.
    Algae may appear, you might need to go back to low low light and work on CO2 again etc.

    My focus here is to really measure and keep the growth nice, but at the lower end and still a little room for wiggling.
    30 micromols should provide that for most species under this tank's condition.
    Color temps of some bulbs also seem to highlight some coloration as well, even if the PAR is identical.

    So there's likely something to the color spectral output of some bulbs as far as red coloration.
    I'm not worried here, since the plants are all green.

    Regards,
    Tom Barr
     
Loading...

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice