The original papers are <"Ullrich CI, Novacky AJ (1990) Extra- and intracellular pH and membrane potential changes induced by K+, Cl−, H2PO4 -, and NO 3 uptake and fusicoccin in root hairs of Limnobium stoloniferum."> Plant Physiol 94:1561–1567 & <"Are Redox Reactions Involved in Regulation of K+ Channels in the Plasma Membrane of Limnobium stoloniferum Root Hairs"> A Grabov, M Bottger - Plant Physiology, 1994.That would be very useful.
That is sort of why I've pushed the <"Duckweed Index">. It has a basis in science, but all the interesting/scary* bits are hidden under the hood.Some people tell me that having a fish tank is very restful, I wonder
*delete as appropriate.Rather than the regular addition of nutrients, I use <"a different approach">. I have a floating plant (usually <"Limnobium laevigatum">) and ,<"heavy planting"> of <"easy" plants"> in the tanks. I just watch the <"growth and leaf colour of the floating plant"> (so not CO2, or light, limited), all the time the leaves are green and the plant growing (how ever slowly) I don't add any nutrients (other than whatever arrives via water changes).
When plant growth (or leaf colour) deteriorates I add some nutrients, once growth has resumed it is back to observing and waiting.
I must admit I like to know how stuff works, not a rivet counter, but the more technical side of 'having a tank' maintains a connection with a past life. Seldom test the water, as you say if the fish and plants are doing well then all is well. However a few toys in the cupboard are a good investment when you are a stand alone.all the interesting/scary* bits
<"Plant blindness">.Still saddened by people who just do not see plants
I haven't seen that one. The estimate is that over half the Earth's oxygen is attributable to Marine Algae, and Diatoms will make up a good proportion of that. The figure quoted is 40% for Diatoms, but the estimates for the proportion of the Earth's oxygen from marine phytoplankton is between 55% - 80%, so that doesn't really help very much.Diatom algae watched a good program on it on netflix 'One Strange Rock'
So as long as you can get below 7.5 PH (like say 7.4), then dosing FE DTPA (hopefully 1-2 hours into the photoperiod), you still have about 60% FE DTPA which is a good amount. You don't need a whole lot, that 60% for a few hours is enough.
The thing about Iron though, is that the plants don't really need a lot and in a high tech tank, within an hour or so the plants has as much Fe as it needs, so it really is not a big problem. If you lost 50% of the Iron then just dose more often and it will get there
Yes I'd just add a pinch, and when you can't see any pink tinge add another pinch, plants don't need a lot of iron. The problem with very hard water is that there aren't any iron ions available, all the iron is combined into insoluble compounds and none of it is plant available.
I can see that Zeus, like me, is also wondering about the dosing method above . Because of EI method, we can dose in excess and not care about Algae, provided you dont go ridiculous amounts (like say a sensible 3ppm FE DTPA versus a ridiculous 50ppm FE DTPA). So if we wanted healthy growth, we could dose thrice per day on Tuesday, Thursday and Saturday (Each dose .33ppm, that will be 9 doses totalling approximately 3ppm)? Would this be okay for livestock like Cardinal Tetra?so this makes me think should I dose my Micro mix with FeDTPA in it in one dump or multiple ? multiple for the photoperiod seems to be the obvious answer to me and easy to do with PLC so three equal doses two hours apart from lights on done
I just gave it some thought today. Since I estimate I have 90% FE-DTPA at 7.1 PH, I could give it an extra half dose. My original target was 1ppm FE per week, new target would be 1.5 ppm.But your surgestion to allow for the the dissociation constant changing with the different pHs so if it's only 50% dissolved dosing double the dose will make the initial dose closer to the target
Think Darrel nails with the ''bioassay'' IMO, what is actually happening on the actual [Fe] isnt important and can be difficult to actually confirm what is happening, but if the plants are better for it and no livestock suffer then its a winner. After all thats EI dosing - dose in excess at safe levels and if the plants are doing well you can try cutting back if you wish and find out how much is actually needed but that takes a lot of time and effort and our tanks requirements are changing all the time as well. Its all right looking at dissociation constants with different pHs but these are done in close to distilled water I would of thought, I would bet with the minimum of other ions present and are tanks are far from that esp if you have hard water which if your using FeDTPA or FeEDDHA you will have so its a case of suck it and see as far as I'm concerned, well thats the way I understand it is,unless someone has some great paper that confirms what is actually going on.@Zeus.'s is the really important point, it doesn't seem very scientific but it works, just watch the plants. Scientists do this, they just call it a "bioassay".
Good, that sounds promising.So I've been dosing Fe eddha for a few weeks now adding tip of a teaspoon as per recomended on this thread and gaining the slight pink tinge, after a week it looked liked my plants perked up abit more vibrant and my Xmas moss started showing alot more growing tips and java fern has sprouted loads of new shoots so all cushty.
I don't have any experience with Purigen and iron chelates, but the pink colour would indicate that you are right, and the FeEDDHA is being removed by the Purigen.I no longer get the pink tinge from eddha and the purigen media is looking pinkish so I can only assume that the purigen is removing the eddha?