- Jan 23, 2005
smik;41873 said:Hi Tom.
Why when there is uptake rates 0,2-0,6 ppm PO4 / 24 hours it is 1.4 -4.2 ppm a week. The EI is added to the tank 4ppm PO4 3 times a week. It is 12 ppm. The smaller dose was not sufficient to cover the consumption of plants?
I am sorry for my english I am use google translator.
Because it's not about consumption and merely adding just enough to make up for the lost. It's about maintaining a reasonably high target range(not a particular ppm).
This is virtually always more than what the plants might use.
So we add more than the uptake of the plants.
The higher ppm's allow more uptake and stability.
Why do hydroponic solutions such as the standard Hoagland's solution use 210 ppm of NO3?
Re: Hoagland's Solution
This is old news.
I think someone is trying to pull the wool over your eyes and suggesting "less is best", or "just enough and no more"
This is not what is done in every other type of horticulture
All (95-98% of all aquatic plants raised for aquariums use a similar hydroponic solution, we cut the %, by 1/5th for submersed culture for fish etc.
But fish are the main reason, not because of plant demand.
Plants adapt to various ppm's using different affinity enzyme systems, so they need less energy to take up nutrients when the nutrients are at higher ppm's.
This is not theory(adaption to various ppm;'s via affinity enzyme uptake systems), this is demonstrated fact in horticulture, in hydroponic systems, in crop plants, in various nutrient and fertilizer test.
I doubt google is going to translate this correctly for you.
Hobbyists need to learn a lot more about how plants grow, and adapt to nutrients before they will understand it.
I try and keep it simple.
But folks wnat to know "why".........so I tell them.