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phosphate diffusion
> From: Stephen.Pushak at saudan_HAC.COM
>
> And a question for our aquatic plant academics, how do we
> determine the optimal nutrient ratios for plants? I suspect:
>
> 1) chemical analysis of plant composition
The following table is based on data from the Feb, 1988 "Today's
Aquarium, the International Magazine of the Optimum Aquarium",
("Aquarium Heute" in German), published by Aquadocumenta Verlag GmbH.
[Yes, it's the Dupla "mouthpiece"]
Average nutrient content of plants and aquarium water
+-----------------------------------------------------------------+
| Symbol Nutrient Plant Water Absorbed as Concen|
| mg/kg mg/l Factor|
+-----------------------------------------------------------------+
| O Oxygen 48,000 880,000 H2O 0.02 |
| Abundantly available in the water |
| |
| C Carbon 36,000 Varies CO2(HCO3-) 1000 |
| Absent if no CO2 injection |
| |
| H Hydrogen 6,000 110,000 H2O 0.02 |
| Abundantly available in the water |
| |
| K Potassium 3,600 5 K+ 1000 |
| Sufficient with good feeding, otherwise fertilizing |
| |
| N Nitrogen 3,200 5 NH4+/NO3- 1000 |
| Too much nitrate with good fish feeding |
| |
| S Sulphur 660 15 SO4-- 50 |
| Source: fish food and mains water |
| |
| Ca Calcium 650 90 Ca++ 10 |
| Absent in soft water |
| |
| P Phosphorus 460 0.1 HPO4--/H2PO4- 1000 |
| Too many phosphates with good fish feeding |
| |
| Mg Magnesium 210 18 Mg++ 10 |
| Absent in soft water |
| |
| Fe Iron 15 0 Fe++/Fe+++ 1000 |
| Absent under good light, unless fertilized |
| |
| Other Trace elements 10 0 Ions 1000 |
| Sufficient with good feeding, otherwise fertilizer |
+-----------------------------------------------------------------+
Notes: "mg/kg" and "mg/l" are roughly parts per million or "ppm"
"Concen Factor" is how much plants can store beyond their needs for
growth, i.e., plants can store 1000 times more iron than they need.
Bummer that all the "interesting" stuff is lumped under "Other" :-(
> 2) observations of natural habitat
There are a couple of tables in _The_Optimum_Aquarium_ that detail
this for a couple of different environments. I haven't seen Tropica's
published analysis of natural habitats yet.
> 3) by controlled experimentation
That's what we're here for. Although "controlled" is up for grabs.
George in Now Ever So Slightly Greener Colorado