allora ho appena avuto risposta dalla redsea, tramite il mitico Giangi.
Il capo scienziato spiega che il ferro è molto subdolo e può cambiare forma molto rapidamente e pertando diventare rapidamente irrilevabile dal test nonostante ce ne sia a sufficienza ed oltre...
Dice ch se il test rileva un aumento da zero a 0,05 dopo aver dosato ferro, significa che se ne è dosato abbastanza.
Ma io dico, possibile che ste cose uno le debba scoprire dopo?????
Che gli costava scriverlo nelle istruzioni, invece di dire che il test è precisissimo e che rileva tutto il ferro presente in vasca a differenza di altri test...
Ecco la sua spiegazione originale:
As you probably know sea water contains many chemicals forms, from free ions through inorganic and organic molecules and up to large colloids connected to metals, this “soup” of chemicals increase the probability of spontaneous reactions causing elements to spontaneously switch between phases.
This phenomena is very typical to iron which is switched between seven forms from soluble free ions (Fe⁺³ , Fe⁺²) through inorganic molecules of Hematite and Ferrihydrate to Organic Iron humate and other colloids ( referred to “chelated” iron ) and up to precipitated iron in aragonite lattice.
The important issue we need to understand is that the iron changes its form all the time based on salinity, pH and most by alkalinity and the amount of organics and colloids in the water.
In a closed system like our aquariums, where there is high organic load and many dissolved organic colloids, the amount of free iron could be very small although the total iron could be very high. Usually this situation will lead to a darkening of the corals due to growth in zooxanthellae population and the outbreak of phytoplankton and other macroalgae, and still you may measure nill levels of iron. From the other hand , on very pure salt water, most iron will be as free iron ions which could be very toxic to the tank inhabitants. This is why when you are adding t colors C to 1 liter you can detect high iron level while few minutes later when you add the iron to the tank you measure levels around 0.05 ppm for several hours and the 0 after 24 hrs. the iron may precipitated or is bond to organics.
Please note that all the forms of iron I mentioned before are interconnected and are activate in all bio-geochemical interactions with the coral and Zooxanthellae algae.
But I had to simplify things for most of the hobbyists who just what to have a nice tank. So during my research and the development of the RCP, I have investigate the complexity of iron bio-geochemistry and I came to several conclusions. The important ones for us a s hobbyist are:
1. Every biological system has its own iron demand and usually its demonstrate different paths of iron consumption and therefore the iron is present in different forms.
2. We need to add iron on constant basis as long as coral grow since iron is precipitated with the aragonite
3. It is difficult to measure all iron form since they change phase all the time
4. It is important not to over dose the system, meaning not increase the levels above 0.25 ppm of soluble iron
5. As long as you can detect after dosage a level of 0.05 for several hrs. you dosed with enough iron.
I came also to the conclusion that the major role for developing the iron test kit will be to help the hobbyist to prevent overdosing of iron where it won’t be bond to organics are precipitated to the coral lattice.
There is a major precipitation especially when people use Kalkwasser due to high Calcium and pH shifts.
Ora infatti ho rimesso la KW per farlo precipitare ed ho tolto il carbone per avere più composti organici che leghino il ferro.
Luca infatti ora sto dando solo due dei 4 elementi (iodio e traccia) ed il cibo, che intendo comunque ridurre.