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Few general questions - LEDs Excel CEC

Mortis

Member
Joined
17 Jun 2009
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410
1] LEDs : When you look at LED emitters, sometimes they give a range for eg 5000-8000k, does this mean that depending on your luck, the LED light will have a colour somewhere in this range ? Or does it mean you can adjust the colour temp by changing the voltage or something ?

2] Excel/Easycarbo : Can regular excess dosing inhibit regular plant growth ? Not talking about sensitive plants

3] CEC : We talk about the CEC of aquatic substrates and their ability to hold nutrients. Does the CEC involve both macros and micros ? As in will the substrate help to retain excess NPK as well as traces that we add via EI dosing ?
How is the CEC of Azoo Plant grower bed/Amazonia ? Ive also heard that adding more K helps to prevent the Amazonia from crumbling easily or something like that is this true ?
 
So no one knows anything about any of these things ? :S
 
Hi mate,
It might be less that no one knows and more that the issues have been discussed at great length and no one has the energy beat a dead horse. It might have been kinder to do a couple of searches. Also, you've mixed 3 or 4 subjects in the same post instead of asking each in it's own sub-forum category, which gets heavy.

Mortis said:
1] LEDs : When you look at LED emitters, sometimes they give a range for eg 5000-8000k, does this mean that depending on your luck, the LED light will have a colour somewhere in this range ? Or does it mean you can adjust the colour temp by changing the voltage or something ?
It can mean lots of things depending on what system you are talking about. When you change the intensity or the amount of light falling on a subject or the amount of energy being emitted by the diode, the color appears to change. The dimmer something is the darker the color rendition. So if the system has a dimming controller, this will affect the color temperature depending on the dimmer setting. This is especially true of a group or cluster if the individual bulbs within the clusters are not the same model and if they have different emission spectra. This question belongs in the Lighting section.

Mortis said:
2] Excel/Easycarbo : Can regular excess dosing inhibit regular plant growth ? Not talking about sensitive plants
It has not been reported that long term use of liquid carbon products degrade the health of plants unless a particular plant is dosed above it's concentration tolerance limit. Degradation can occur due to excessive concentration or due to insufficient concentration. This question belongs in the CO2 section.

Mortis said:
3] CEC : We talk about the CEC of aquatic substrates and their ability to hold nutrients. Does the CEC involve both macros and micros ? As in will the substrate help to retain excess NPK as well as traces that we add via EI dosing ?
CEC stands for Cation Exchange Capacity so it is only relevant for cations, i.e. positively charged particles. Micronutrients, mostly being metals, are typically cations such as Fe+ for example. that is what the "+" indicates. Cation Macros are K+ and NH4+. But sediments also have AEC, which is Anion Exchange Capacity. Anions are negatively charged particles. Examples of micronutrient anions are Chloride (Cl-) or Sulphate (SO4--). Examples of Macronutrient anions are Nitrate (NO3-) and Phosphate (PO4--- or H2PO4-). Clay and humus in soils have surfaces that hold charged particles on them. Due to electrostatic forces in the water surrounding the sediment particles, the anions and cations move back and forth on the surface in the same way that anions and cations move back and forth on the terminals in a battery. So a typical cation, such as H+ will be pulled away from the clay/humus surface, and the change in the surface charge caused by the departure of H+ will then cause some other anion to be attracted to the surface, such as K+.

If a plant's root hair is attached to the clay surface, it will attract the K+ thus causing the surface of the clay particle to have a new charge, which will then attract another cation from the water. This is the basic mechanism for the general concept of soil fertility. So there is constant movement of positive and negative charges across the surface of the sediment particle to and from the water surrounding the clay surface, as well as to and from the root hair attached to the clay surface. Thus the second word "Exchange" in the phrase. "Capacity" refers to the total number of available "slots" on the surface, on a per unit weight basis that can hold one H+ cation. Different soil types, and different clays have a different capacity based on their particular chemical structure, therefore some are considered more "fertile" than others. The capacity is measured in units known as millequivalent per 100 gram of sediment. The higher the number, the higher the fertility, because it can attract more cations per unit weight.

Mortis said:
How is the CEC of Azoo Plant grower bed/Amazonia ?
Unless Azoo identifies the type of clay, or the dominant mineral it contains, which allows you to then go to a CEC chart to look it up, or unless they explicitly state the meq/100g, we do not know the answer to that question. However, if it is a clay or clay/humus combination, then we can say that it is good-very good because generally clay and humus sediments are generally good to excellent (Kaolinite containing clays being an exception). If the particles are made of sand then it is middling to poor. It also depends on how it's been treated, so if it is clay a lot will depend of whether it was baked or not. Here are some general numbers I dug up:
Vermiculite Clay - 100-150meq/100g
Smectite Clay - 80-100meq/100g
Organic/Humus 50-100meq/100g
Clay/Clay Loam - 20-50meq/100g
Illite Clay - 15-40meq/100g
Silt Loam - 15-25meq/100g
Loam - 10-15meq/100g
Dark Sands 10-20meq/100g
Kaolinite Clay 3-15meq/100g
Light Sands 3-5meq/100g

it's also generally stated that not all cations are attracted to the surface of the sediment equally. the following is the general attraction priority, listed in order or descending attraction:
Al+++=>Ca++=>Mg++=>K+, NH4+=>Na+
The higher the pH, the greater the attraction. The higher the concentration of a given cation the greater the attraction. Plant roots also have their own CEC/AEC and they normally release H+ onto the sediment surface.

Mortis said:
Ive also heard that adding more K helps to prevent the Amazonia from crumbling easily or something like that is this true ?
I have not seen data supporting this. I don't think the dissolved K+ would find it's way into the molecular structure of this clay. Illite type clays, for example, are rich in the mineral "mica" in which K forms part of the molecular structure, but I doubt dosing K+ could affect this structure. You normally have to bake a clay to hundreds of degrees in order to affect or change it's structure.
These three questions should have been submitted in the Substrate sub-forum.

Cheers,
 
Thanks a lot for the info ceg !! I apologize of I came across as being an ass. I was planning on on splitting the posts up into the individual forums but then thought it might be better to have all of it together in one place. I'll create separate posts in the appropriate sub forums next time.
 
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