Quick EI question

[Victor]

Could we dose all week EI dosing at once? For example, each saturday I intend to dose for all week something like 50 ppm of KNO3, 6 ppm of PO4, 10 ppm of Mg, 10 ppm of Ca + micros nutrients. There is any concern about this? If yes, why? Thank you.

 

[Marcel G]

You can dose once a week all the chemicals which are stable enough in your aquarium (under the given light intensity and temperature) to "survive" for the whole week.
That's usually not case of chelated nutrients, especially iron. The only chelate, I know of, which can "survive" for about week (without degrading which would cause the iron precipitation) is Fe-DTPA. I tested Fe-gluconate, Fe-EDTA, Fe-DTPA and the combination of Fe-DTPA + Fe-EDDHMA. All chelates except Fe-DTPA degraded the next day after I added them to my test tanks. The worst precipitation issues were in the tank with Fe-gluconate. I should note, that I used 0.9 ppm of Fe in all the tanks (so quite high dosage). If you divide your weekly dose of iron into smaller dosages, the precipitation issue may not be that bad.

PS: The iron precipitated even without PO4 in the water.
Look here for more info and pictures.

 

[parotet]

I thought there were other nutrients that could be also uptaken by the filter/substrate and remain unavailable for the plants, ins't it? what about phosphates and potassium? I was reading some days ago an ADA catalogue I was given, and they point out the need of fertilizing as close as possible to the lights on to avoid nutrient losses absorbed by other things than plants. Not sure if it makes sense, as the plants do really uptake nutrients 24/7. Maybe their uptake peak is at the beginning of the photoperiod?

Jordi

 

[Marcel G]

I'm not knowledgeable enough, but I doubt potassium (K) may become unavailable to plants in aquarium water under normal conditions. In some cases calcium (Ca) may become unavailable in presence of some chelates (as it can replace iron in the chelate). Also under high pH and high concentration of Ca(+2) the calcium can cause some chelates to degrade and break down (according to what I have read). As to the phosphates, as they are the most limiting factor in most aquatic ecosystems, the living organisms have learned to uptake it really quickly (and store it for future use), so it's probable that a couple of hours after you add photosphates into your tank, they will "dissapear" (they can be succked up by substrate, plants, or other organisms). Also phosphates can precipitate is you have high level of iron ions in water (which can be the case only when your Fe-chelates breaks down). In such a case the PO4 will bing to Fe forming an insoluble precipitate.

So it all depens on the concentration of these nutrients, chelates used, and pH.

 

[parotet]

s to the phosphates, as they are the most limiting factor in most aquatic ecosystems, the living organisms have learned to uptake it really quickly (and store it for future use), so it's probable that a couple of hours after you add photosphates into your tank, they will "dissapear" (they can be succked up by substrate, plants, or other organisms)

Are they unavailable for the plants when they are stored in the substrate, or can it be considered a temporary stock system to make them available when needed?

Jordi

 

[ian_m]

Are they unavailable for the plants

They become unavailable to the plants as insoluble salts. Only extreme acidic conditions (like not found in tank) will make them soluble again.

 

[ian_m]

Could we dose all week EI dosing at once?

It doesn't work like that, the plants would suffer due to the wildly varying nutrient levels. People who have tried it long term suffer algae and poor plant health.

I suspect upon dumping the excess nutrients in the water, the plants scoff the lot very quickly leaving none for the rest of the week, thus start suffering and producing algae.

Also the there are long term health implications for your fish in such high levels of nitrate.

EI is designed to provide a constant supply of nutrients to the plants.

If you aren't around to dose daily then either EI isn't for you or get a set of dosing pumps, about £70 from Ebay nowadays. I use dosing pumps.

 

[Marcel G]

They become unavailable to the plants as insoluble salts. Only extreme acidic conditions (like not found in tank) will make them soluble again.

I agree with that just in part. In some kind of substrates there are organics (like tannis or other humic substances) which can bind some nutrients (probably phosphates also) and in this form they should be available to plants. Also, the "extreme acidic" conditions you mention may be created by roots deeper in the substrate. Plants have learned to utilize the oxidized form of nutrients using their own acids and chelates (like citric acid). So the plants (using their roots) are able to uptake even the unavailable nutrients, although they do it only under the conditions of extreme deficiency (at least, that's what I have read).

 

[Marcel G]

The plants would suffer due to the wildly varying nutrient levels. People who have tried it long term suffer algae and poor plant health.

Sorry to disagree again, but I don't think plants are too much stressed by changing levels of nutrients. In hydroponics people use much, much higher nutrient concentrations then we use, with great success. I myself am right now using 90 ppm NO3, 9 ppm PO4, 60 ppm K, 0.9 ppm Fe in my test tanks, and the plants (Pogostemon and Ludwigia) seems to have no problems with it. I dose it once a week, then I change 100% of water, and dose it again. I had just a little algae issues (which is quite normal under such conditions). But I admit that our plants can experience some problems in case we have there a combination of fast-growers with slow-growers, as the slowly growing plants won't be able to gain the same amount of nutrients as the fast-growing ones, so they may probably suffer.

One more thing:
Plants, for sure, grow faster if they have more nutrients available. So under 30 ppm NO3 etc. (dosed once a week) they will grow much faster than under 5 ppm NO3 (dosed on daily bases). Why? Because plants are able to utilize just a small part from the total external concentration available (say 10%). So 10% from 30 ppm means more than 10% from 5 ppm => What's more? 3 ppm x 7 days (= 20 ppm) or 0.5 ppm x 7 days (= 3.5 ppm)?

 

[ian_m]

It is the iron phosphate from reaction of chelated iron and potassium phosphate that react for form insoluble iron phosphate. Terrestrial plants under certain circumstances can get access to this phosphate, but not to sure aquatic plants ever can. In fact the phosphate run off from farmers field is often the "insoluble" phosphate in the soil rather than the phosphate fertiliser the farmer has applied. Fertilising the plants makes them search out more nutrients making the soil acidic, thus releasing the bound phosphate in the soil for the plants to use as well as get washed away into water courses.

People dosing macro and micro at the same time have experienced plant iron deficiency symptoms, which is cured by dosing alternate days. Also there have been reports that using EDDHA chelated iron resists the phosphate reaction (as often used in commercial all in one fertiliser), but EDDHA costs quite a bit more than normal EDTA iron.

 

[Paulo Soares]

Could we dose all week EI dosing at once? For example, each saturday I intend to dose for all week something like 50 ppm of KNO3, 6 ppm of PO4, 10 ppm of Mg, 10 ppm of Ca + micros nutrients. There is any concern about this? If yes, why? Thank you.

Tell me something guys..
If we know that plants have a maximum absortion rate around 20 PPm why the hell is this figures? 50 PPM?

T. Barr states that we should give the maximum intake with a little excess. This excess is the one taken out in the weekly WC.

Best regards

 

[Marcel G]

If we know that plants have a maximum absortion rate around 20 ppm why the hell is this figures? 50 PPM?

First of all, we don't know the maximum uptake rate of our plants. What T.Barr says is some data based on his experiences (although we don't know the methodology of how he came to such results). I asked him several times how he came to such numbers, but he never explain it in detail.

Second, the amount of nutrients in water column is not the same as the amount our plants are able to uptake. This is very important to know and understand! As I already mentioned, if you have nutrient-rich substrate + 30 ppm NO3, 3 ppm PO4, 0.5 ppm Fe in water column + strong light (100 µmol PAR at the substrate) + high CO2 levels + good flow in your aquarium, your plants may consume up to 10 ppm NO3 per week (~30%). If you have nutrient-rich substrate + 10 ppm NO3, 1 ppm PO4, 0.5 ppm Fe in water column + strong light + high CO2 levels + good flow in your aquarium, your plants may consume up to 3 ppm NO3 per week (~30%). You can look at my test here. From this you can clearly see, that the growth rate of aquatic plants depend very much on the external concentration of nutrients. If you want your plants to consume 10 ppm NO3 per week and grow in heigh by say 10 cm (4 inches), then it's not sufficient to supply them with 10 ppm NO3 ... you have to supply them with 30 ppm NO3 (or even more if you don't have any nutrient-rich substrate)! So to say that some plant species grow at their maximum at 30 ppm NO3, does not mean that these plants are able to use this all up in one week. It just means that under the external concentration of 30 ppm NO3, they will grow best. But in reality, the plants may be able to "bite" just a small portion from this "pie". If you give your plants 10 ppm NO3, they may be able to eat up only 3 ppm per week (or maybe even less). This is especially true of iron. Some plants grow best at 8 ppm Fe in the water column. But does this mean that they eat this whole amount up? No! But under this concentration, the uptake of iron is the biggest they are capable of (although in reality they may consume just 0.005 ppm per week from this 8 ppm amount in water). So let's assume for now, that our plants are able to consume 1 to 30% of the available nutrients (depending on the actual nutrient and the exact conditions in your tank => flow, light, substrate, temperature etc.). So 30 ppm NO3 in water column = 10 ppm NO3 uptake by plants, 10 ppm NO3 in water column = 3 ppm NO3, etc. To complicate it even more, each plant has different growth rate and different optimal nutrient concentration. For example, Vallisneria is said to grow best at 90 ppm NO3 in water column (but for sure, it will grow well even under 10 ppm NO3 ... just a little slower). The same applies for PO4, Fe, CO2 ... light. There is no universal concentration which can be optimal for all plant species! Some plants may need up to 8 ppm of iron to grow best, while for others this concentration may be downright toxic. I don't know of anyone who is making any experiments which would help us to know what are the optimal conditions for different plant species. T.Barr said that he did some experiments, but he never published any solid data to back it up, and based on what he's saying elsewhere I just don't believe him (sorry to say this) ... but I am just no one, while he is guru, so my words have no relevance.

 

[Paulo Soares]

Your words have relevance to me! Cause i´m with you 100% since i started to read your posts in this forum and some discussions with Ceg
I´m also a NON believer of Ei methods. Never was.
I also asked a few questions that never got answered..

He´s the one who stated the uptake rates. I only put another card in the table to your conversation. For me "Ei" is over. Done for good for quite a while now. .

Best Regards.

 

[Marcel G]

On one hand, I respect Tom Barr for his enthusiasm and his contribution to our hobby. For sure, he has much more experiences than I have. Also, without him I would probably never question some "truths" in our hobby. I have to admit that once I believed him as well as his EI method and was a strong proponent of it. Maybe one day I'll find out that he's really right. But for now I have some doubts and some data which convince me of the opposite. What I really don't understant is why T.Barr do not publish his findings (if it's true that he did so many experiments with aquatic plants)? I asked him all these questions many times ... without any answer. So right now I do my own experiments to find out some answers to my questions. I cooperate with prof. Cizkova from Faculty of Agriculture at University of South Bohemia => she helps me with the methodology. So I hope I'll have soon some serious data we all can build upon.

 

[Paulo Soares]

I´m also working with professors, investigators and others here in Portugal.

They are helping me in some matters and issues.

Hope one of these days we could change information.

I´ll give one thing i almost have for shure now.
It seems to me that no one should add PO4 in Ei in the first three months of a tank. Only KNO3 and KCL.

The tank it self provide PO4 in is own conversion. We should only had extra Potassium for the reasons you certainly know.
Most of our friends having issues with BBA or Diatoms in the first months of a living aquarium were using EI with lots of PO4..
Those who never did put PO4 never have any algae.

I have taken many notes from dozens of tanks and compare.
And this i conclude.

Best Regards.

 

[xim]

Also there have been reports that using EDDHA chelated iron resists the phosphate reaction (as often used in commercial all in one fertiliser), but EDDHA costs quite a bit more than normal EDTA iron.

EDDHA is just 30% more expensive than EDTA. But the problem is its colour.
It's like adding potassium permanganate, the whole tank turned dark pink even with small dose.
I've tried it.

 

[ian_m]

EDDHA is just 30% more expensive than EDTA. But the problem is its colour.

Ah, that's why. I remember reading about the first EI & PMDD experiments, years ago, about dosing macro and micro together and that EDDHA got round the reaction issues in the tank, but I thought it got dropped due to cost at the expense of dosing alternate days. I know now why.

This page has some chelates being dissolved with pink/red colour. Also states EDDHA compatible with soluble phosphates where as EDTA isn't and you get a precipitation.
http://uk.solufeed.com/products/chelates

 

[xim]

Yeah, that colour.

That page states DTPA is also compatible. Although I think it's not as stable as EDDHA.
Fortunately DTPA is good enough, I'm using it.

 

[Victor]

Also the there are long term health implications for your fish in such high levels of nitrate.

But nitrates aren't toxic for fishes even in a very high level (300 ppm +)

 

[Marcel G]

That page states DTPA is also compatible. Although I think it's not as stable as EDDHA.
Fortunately DTPA is good enough, I'm using it.

In fact, I think the Fe-DTPA can be more stable than Fe-EDDHMA (at least according to my little experiment).