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[APD] Re: LCP(light compensation point)



Regarding my so called "expertise" with growing plants and the rest of folks needing more light/help to get them to the promised land:
It's not a question of me being some sort of expert and that the rest of the folks have to try doing things _other_ than I suggest to eek by (such as adding very high light for good reds) is some how your only option/s........or will help you in the quest, been there done that a long time ago. 
 
High light is all the rage and has been for about 6 years or more now. It's a myth about producing better reds etc.
 
Many folks wonder how these folk's in other lands grow such nice reds, well, I'm telling you, less light=> more stable low NO3, more NH4 ratio added to the N needs as well, less algae(algae do like more light)  
 

 I also could grow plants very well with high PO4 way back when also, I was proved right even though the dogma at the time suggested otherwise. I might know more about aquatic photosynthesis than the average hobbyist. Common sense plus a good method/s can go a long long way. Even a smart person can easily get befuddled with the wrong information/assumptions if they do not how to use it with some degree of common sense.   
 
BTW, George Booth has been growing Eustralis for a very long time with those lower light levels(2w/gal is high light to him with NO FL's) and so did Steve Dixon(Gloss, R macrandra/wallichii, tennellus etc), so for the folks that do enjoy "crow", please have seconds.
 
Controlling the nutrients and CO2 is possible, adding less light is also possible.
It's only 3 basic things to play with, no rocket science needed as far the "how".
It's something anyone can test out and do not need any educational or experience background to try. Testing is mainly an issue of CO2, nutrients can be dosed effectively using water changes and frequent dosing, so then all that is left is lighting for your variable.
 
Unless you actually try it and try it by controlling the other parameters(nutirents and CO2), you often have a difficult time understanding it or proving to yourself that it actually works or not. I'll say the same thing as I did with PO4, try it and see for yourself.
 
Then you'll know. 
Rather than believing in "magic waters, or that guy can grow anything".
James did pretty well with less than a year's experience at last year's AGA, he won.
 
I define LCP as the point where the plant's production of starch/food is equal the the plant's maintenace requirements for health.
 
So LCP=> Photosynthesis production = respiration by the plant.
 
In order to find this, you need non limiting nutrients/CO2.
So my advice still stands quite firm and it will only improve your tank by improving CO2/nutrient routines levels.
 
Adding more light beyond the LCP will yield growth, less will yield decay and depletion and eventual death.
 
As far as units, micro moles of photon's(or Einsteins/units of quanta) are the best units for light and what are used in the research which is best for comparisions.
A few folks may have lux meters etc and they may be close etc so it certainly is better than nothing. I'm not bothered enough by the issue yet to really go through the plant list and try out each species to find some 200 species' LCP that have never been tested for.
 
I think perhaps 15 or so species have been tested for LCP. The range varies but generally it's very low. I would expect any plant that is successful in th aquatic habit to be roughly similar in respect to this.
 
You may search on IFAS's web site for more back ground research on Aquatic photosynthesis, George Bowes has done a fair amount of research on Hydrilla over the years, there's also some on Myriophyllum, Pondweeds, a few others by various authors.
 
Regards, 
Tom Barr
 
 
 
 
 
 
 
 
 
 

		
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