BHornsey;14754 said:
Hi Tom,
Just a query but I thought the principle of EI was to provide a simple method to dose nutrients for any tank, to prevent anything from running out (plant deficiency) which I assumed to be regardless of bio-mass?
No,
But it's not that clear in the EI article to be honest.
50% of the surface area and generally lots of faster growing plants, or else less lighting etc, can be used as you get closer to less biomass.
It's not going to be a distinct % or biomass I think due to lighting, plant species and user issues.
But more is generally better.
Dense as you can go.
I (finally!) understand that excess growth, driven by high light, causes problems for low growing plants; I've had a lot of bad experience with this, but this thread has caused me some thoughts.
I had presumed that you dosed to a level to be sufficient for good growth. If uptake isn't high it wouldn't matter, plants use what they need and leave what they don't; levels won't become excessive as water changes reset the levels.
To some degree.
But.......consider this:
A tank with 3x as much plant biomass vs the same tank, light etc, with the regular biomass.
Now if you added say 40ppm per week of NO3, you might predict something like 2-3x as much uptake, thus the range would be between say 20-30ppm of NO3 with high biomass, with less? Maybe 50-70ppm.
These are not critical though.
What are critical issues?
How do you think this same issues applies to NH4?
More or less?
Assume light/CO2 are the same.
Now try this same issue with a set stable CO2 input(note this means that CO2 bubble mrate coming into the tank is the same throughout).
What do you think would occur if you have say 35ppm of CO2 with regular biomass then increased it 3x?
It would no longer be 35ppm would it?
It would likely be less, much less, about 10-15ppm or so.
Now how would NH4 uptake also be influenced knowing what you know about how carbon and nitrogen uptake regulate eachother as one becomes limiting?
Would you expect less NH4 with 3x the biomass under a CO2 limitation at 10pppm of CO2? Most would say yes.
I would not actually.
With high CO2 with less biomass, you have intense uptake for those plants.
With low and unstable CO2, the plant goes into shock and reduces, or "
downregulates" NH4 uptake to match the carbon supply.
So it depends on the various other confounding issues like CO2 and it's control over NH4 uptake etc as well.
Cool huh?
Regards,
Tom Barr