Is EI enough?

[Christos Ioannou]

Are we still talking about a hobby or rocket science?!

Sent from my A0001 using Tapatalk

 

[Jose]

It's more easy to dose all at once because I usually forget to dose some days during the week. I'll dose after after wc the following amount of macros, 60 ppm KNO3, 8 ppm PO4, 10 ppm Mg and 30 ppm Ca.

Give it a go and we'll see. Light will make the difference (if its low or high).

 

[Victor]

I think it's medium/high. I have 3 lines of T8 (6 x 30 w) over my tank (200 cm x 40 cm x 45 cm) and each bulb have a good reflector. This weekly dosing schedule works better with high light?

 

[Jose]

I think it's medium/high. I have 3 lines of T8 (6 x 30 w) over my tank (200 cm x 40 cm x 45 cm) and each bulb have a good reflector. This weekly dosing schedule works better with high light?

No. The faster your plants will grow the more you have to stick to "EI" rules. So, the more light you have then the more stable the concentration should be so as not to run out of anything at any time.
Basically if you have high light then plants will grow faster, so they'll need more nutrients at all times. Also the faster they grow the more waste they produce so more water changes are needed. This has nothing to do with the method but all to do with plant growth.

 

[Victor]

No. The faster your plants will grow the more you have to stick to "EI" rules. So, the more light you have then the more stable the concentration should be so as not to run out of anything at any time.

So I think there will be no problems because I'll dose 2x the weekly EI macronutrients dosage at once. Sixty ppm KNO3, 8 ppm PO4, 10 ppm Mg and 30 ppm Ca is a lot, isn't it?

 

[Marcel G]

Are we still talking about a hobby or rocket science?!

As long as everything goes well, you don't need to know any science behind it. But as soon as things go wrong and you don't understand why, then it's time to go deeper. My posts are meant to help you understand why iron may precipitate in your tank (or why you can experience iron deficiencies in your plants). If you don't have any problems with iron, and are not interested in any knowledge about planted tank science, then just ignore it.

 

[Marcel G]

I'm thinking to dose all macronutrients weekly dosage at once (after water change). But I'll keep dosing micros in alternated days (because the most part of them are chalated). It's a good idea?

As far as I know, the growth rate of plants and their uptake of nutrients depend on the external concentration of these nutrients in water and/or in substrate. What does this mean? This means that if you have, for example, 30 ppm NO3 in your water, your plants will produce about 1 gram of biomass per week. If you give them just 10 ppm NO3, your plants may produce only about 0.3 grams of biomass per week. So the higher the concentration of nutrients in water or substrate, the more biomass is produced (the higher the growth rate). Of course, each nutrient concentration has its upper limit.
So if you supply your plants 30 ppm NO3 in one weekly dose, the first day your plants will have 30 ppm NO3 available and from this amount they uptake, say, 10% each day:
1st day: 30 ppm NO3 available => 3 ppm uptaken (10%)
2nd day: 27 ppm NO3 available => 2.7 ppm uptaken (10%)
3rd day: 24.3 ppm NO3 available => 2.4 ppm uptaken (10%)
4th day: 21.9 ppm NO3 available => 2.2 ppm uptaken (10%)
5th day: 19.7 ppm NO3 available => 2.0 ppm uptaken (10%)
6th day: 17.7 ppm NO3 available => 1.8 ppm uptaken (10%)
7th day: 15.9 ppm NO3 available => water change
Weekly consumption of NO3 by plants under one 30 ppm weekly dose = 14.1 ppm NO3

On the other hand, when you supply your plants the NO3 on daily basis => 4.3 ppm NO3 each day (7 x 4.3 = 30 ppm per week):
1st day: 4.3 ppm NO3 available => 0.4 ppm uptaken (10%)
2nd day: 8.2 ppm (3.9+4.3) NO3 available => 0.8 ppm uptaken (10%)
3rd day: 11.7 ppm (7.4+4.3) NO3 available => 1.2 ppm uptaken (10%)
4th day: 14.8 ppm (10.5+4.3) NO3 available => 1.5 ppm uptaken (10%)
5th day: 17.6 ppm (13.3+4.3) NO3 available => 1.8 ppm uptaken (10%)
6th day: 20.1 ppm (15.8+4.3) NO3 available => 2.0 ppm uptaken (10%)
7th day: 18.1 ppm NO3 available => water change
Weekly consumption of NO3 by plants under seven small daily doses = 7.7 ppm NO3

Now, in which case your plants will uptake more nutrients, thus producing more biomass and growing faster?
I would say that you plants will grow almost 2-times faster if you supply them 30 ppm NO3 once a week, rather then dividing them this amount into seven smaller daily doses.

With trace elements the situation is a little different. On the one hand, it works the same (i.e. if we can dose just one bigger dosage of micros our plants will gain much more of it and grow probably better), but on the other hand, iron chelates won't last too long in our tanks, so it's much wiser to dose them on daily basis, rather than just once a week.

 

[Victor]

As far as I know, the growth rate of plants and their uptake of nutrients depend on the external concentration of these nutrients in water and/or in substrate. What does this mean? This means that if you have, for example, 30 ppm NO3 in your water, your plants will produce about 1 gram of biomass per week. If you give them just 10 ppm NO3, your plants may produce only about 0.3 grams of biomass per week. So the higher the concentration of nutrients in water or substrate, the more biomass is produced (the higher the growth rate). Of course, each nutrient concentration has its upper limit.
So if you supply your plants 30 ppm NO3 in one weekly dose, the first day your plants will have 30 ppm NO3 available and from this amount they uptake, say, 10% each day:
1st day: 30 ppm NO3 available => 3 ppm uptaken (10%)
2nd day: 27 ppm NO3 available => 2.7 ppm uptaken (10%)
3rd day: 24.3 ppm NO3 available => 2.4 ppm uptaken (10%)
4th day: 21.9 ppm NO3 available => 2.2 ppm uptaken (10%)
5th day: 19.7 ppm NO3 available => 2.0 ppm uptaken (10%)
6th day: 17.7 ppm NO3 available => 1.8 ppm uptaken (10%)
7th day: 15.9 ppm NO3 available => water change
Weekly consumption of NO3 by plants under one 30 ppm weekly dose = 14.1 ppm NO3

On the other hand, when you supply your plants the NO3 on daily basis => 4.3 ppm NO3 each day (7 x 4.3 = 30 ppm per week):
1st day: 4.3 ppm NO3 available => 0.4 ppm uptaken (10%)
2nd day: 8.2 ppm (3.9+4.3) NO3 available => 0.8 ppm uptaken (10%)
3rd day: 11.7 ppm (7.4+4.3) NO3 available => 1.2 ppm uptaken (10%)
4th day: 14.8 ppm (10.5+4.3) NO3 available => 1.5 ppm uptaken (10%)
5th day: 17.6 ppm (13.3+4.3) NO3 available => 1.8 ppm uptaken (10%)
6th day: 20.1 ppm (15.8+4.3) NO3 available => 2.0 ppm uptaken (10%)
7th day: 18.1 ppm NO3 available => water change
Weekly consumption of NO3 by plants under seven small daily doses = 7.7 ppm NO3

Now, in which case your plants will uptake more nutrients, thus producing more biomass and growing faster?
I would say that you plants will grow almost 2-times faster if you supply them 30 ppm NO3 once a week, rather then dividing them this amount into seven smaller daily doses.

With trace elements the situation is a little different. On the one hand, it works the same (i.e. if we can dose just one bigger dosage of micros our plants will gain much more of it and grow probably better), but on the other hand, iron chelates won't last too long in our tanks, so it's much wiser to dose them on daily basis, rather than just once a week.

Excelent explanation, mate! Thank you.

 

[Victor]

Do you think 60 ppm KNO3, 8 ppm PO4, 10 ppm Mg and 30 ppm Ca once a week can provide the maximum daily uptake? Or I need more to reach the daily uptake limit by plants?

 

[Jose]

1st day: 30 ppm NO3 available => 3 ppm uptaken (10%)
2nd day: 27 ppm NO3 available => 2.7 ppm uptaken (10%)
3rd day: 24.3 ppm NO3 available => 2.4 ppm uptaken (10%)
4th day: 21.9 ppm NO3 available => 2.2 ppm uptaken (10%)
5th day: 19.7 ppm NO3 available => 2.0 ppm uptaken (10%)
6th day: 17.7 ppm NO3 available => 1.8 ppm uptaken (10%)
7th day: 15.9 ppm NO3 available => water change
Weekly consumption of NO3 by plants under one 30 ppm weekly dose = 14.1 ppm NO3

On the other hand, when you supply your plants the NO3 on daily basis => 4.3 ppm NO3 each day (7 x 4.3 = 30 ppm per week):
1st day: 4.3 ppm NO3 available => 0.4 ppm uptaken (10%)
2nd day: 8.2 ppm (3.9+4.3) NO3 available => 0.8 ppm uptaken (10%)
3rd day: 11.7 ppm (7.4+4.3) NO3 available => 1.2 ppm uptaken (10%)
4th day: 14.8 ppm (10.5+4.3) NO3 available => 1.5 ppm uptaken (10%)
5th day: 17.6 ppm (13.3+4.3) NO3 available => 1.8 ppm uptaken (10%)
6th day: 20.1 ppm (15.8+4.3) NO3 available => 2.0 ppm uptaken (10%)
7th day: 18.1 ppm NO3 available => water change

This is misleading. Nutrient uptake is not linear to concentration in the water. There is a relationship though: The more nutrients in water then the more uptake there is. But there is a non or near non limiting value after which a big change in nutrients doesnt mean an important change in growth.

EI is meant to maintain (supposedly and I havent done tests on this but most people have had great results) that near non limitting concentrations via dosing on alternate days.

Plus the idea behind dosing on alternate days also solves any problems you might have with precipitation or ion exchange processes.

 

[Marcel G]

Do you think 60 ppm KNO3, 8 ppm PO4, 10 ppm Mg and 30 ppm Ca once a week can provide the maximum daily uptake? Or I need more to reach the daily uptake limit by plants?

Hardly anyone can answer this question. But for sure, each plant species has a different optimum concentration level. Still, I would say that the suggested concentration should be very close to the upper limit for most plants.

 

[Marcel G]

This is misleading. Nutrient uptake is not linear to concentration in the water. There is a relationship though: The more nutrients in water then the more uptake there is. But there is a non or near non limiting value after which a big change in nutrients doesnt mean an important change in growth.

Do you think my values (3 ppm, 2.7 ppm, 2.4 ppm, 2.2 ppm, 2.0 ppm, etc.) are linear?

 

[Jose]

Do you think my values (3 ppm, 2.7 ppm, 2.4 ppm, 2.2 ppm, 2.0 ppm, etc.) are linear?

Not the values. The percentage uptake should also not be linear. Basically youve given an example where levels of nutrients are quite limitting. This levels are different for different plants and for some 10 ppm of NO3 might be non limitting whilst for others it might be 90. I understand you are just giving an example but people need to understand that this is not always this way. If we are over the non limitting levels for a given plant then uptake if we stay in that range will be quite similar in both cases.

 

[Marcel G]

Not the values. The percentage uptake should also not be linear. Basically youve given an example where levels of nutrients are quite limitting. This levels are different for different plants and for some 10 ppm of NO3 might be non limitting whilst for others it might be 90. I understand you are just giving an example but people need to understand that this is not always this way. If we are over the non limitting levels for a given plant then uptake if we stay in that range will be quite similar in both cases.

Yes, I agree with this, but I rely on people having a brain, that they can use. The values were really just an example. It's very hard to monitor the nutrient uptake on daily basis, because if you would like to know how much nutrients your plants uptake each day, you would have to do a lot of analysis each day. Most scientific studies monitor plant growth for some period of time (say, couple of weeks), and do all the analysis at the end of this period. Then they calculate the average uptake per day (or per week). So we, in fact, don't know if the uptake percentage is linear or not. I just wanted to show some general mechanism of nutrient uptake, i.e. that it really matters what external concentration you have in your tank, and that plants can uptake just a small part (a certain proportion or percentage) of what they have available in the water or substrate. So there will be a big difference in supplying them with 70 ppm once a week vs. 10 ppm each day. That's all. The exact numbers do not matter; what matters is the logic → the mechanism. But if we want to be clear in what is the optimum concentration of nutrients for different species, someone will finally have to do the experiments. Otherwise, we will be forever locked in the realm of speculations.
I myself am already doing some tests, which can help us to answer few of these questions:

The above chart shows two plants grown under 90 ppm NO3, 9 ppm PO4, 60 ppm K, 0.9 ppm Fe (all weekly doses), 35-44 ppm CO2, 25-28°C, 100-200 µmol/m2/s. It was just a sample. Right now I'm doing a complete experiment with growing five aquatic plant species under different concentrations of nutrients.

The first test is being done with Pogostemon erectus.

 

[Christos Ioannou]

Its about time that I added some pictures to get the most out of you people.

This is an FTS of my tank. Its 180L tank, running on a 2000LPH filter. Water is returned in the tank with a tank-long spraybar. Water spray will hit the front of the tank with a small arch. CO2 is fed via an inline DIY Rex Crigg style reactor that effortlessly sets the drop checker to lime green (or more likely light yellow). The liquid in the drop checker is from Aquasabi that is registering 30ppm with a green color. So its a definite > 30ppm @ substrate level. I don't bother counting BPS of CO2. Lifestock is doing ok due to surface rippling. I am also running a surface skimmer (addon to the filter intake)

Tank is running between 26/27 degrees celcius (hot summer has arrived, temperature outsite is about 38-40 degrees)

Substrate is Tesco's Kitty Litter (molar clay) and sand.
Light is 2x54W T5 20cm above water line; 55cm above substrate. I was using CFL lights but switched to T5 about a month ago.

These are the plants and how they look:

MONTE CARLO. Suffered from algae, treated with H2O2. This burned badly the MC (about a month ago). I think it is now recovering but its veeeery slow in doing so.

S. REPENS. I was dosing lean on the MICROS so leafs turned a pale yellow. This was identified a couple of weeks back and fixed. Seems to be getting back on track. Older leafs suffer from some bba. Also some leafs appear torn.

E.PARVULA. Is doing quite alright after I switched from CFL light to T5. Its sitting below the spraybar at the back of the tank so I suppose it is getting very little flow in the tank.

ALTERNANTHERA REINECKII sp mini. (or a pathetic excuse of this) I had to trim it back since the leafs show a pale pink color. Lower leafs suffer from GSA(?) This is also at the back of the tank. When I initially changed to T5 the color was amazing! Now its like in the pictures...

POGOSTEMON HELFERI Sits on the back of the tank. Usually I trim tops and replant. Was growing out leggy before switching from CFL to T5.

Mosses are thriving (christmass moss and weeping moss). Those were trimmed back yesterday.
Hydrocotyle tripartita, hygrophila polysperma, crypts are doing ok as well.
BBA is greatly reduced after introduction of 5 Yamato shrimp (adding more next month)

Dosing (EI)
I am using the following:
MICRO: chelated trace elements from APF, 6g in 500ml solution, 50ml daily. (APF recommended dosage)

MACRO: KNO3, KH2PO4

KNO3: 25g in 500ml, dose 50ml 3 times / week giving 3*8.5ppm Nitrate (33,5ppm Nitrate weekly) and 5.38 ppm Potassium (16.05ppm K weekly)

KH2PO4: 7,5g in 500ml, dose 50ml 3 times / week giving 3*1.2ppm Potassium (3.6ppm K weekly) and 3*2.89 ppm Phosphate (8.7ppm Phosphate weekly)
(results using Jame's calculator)

Weekly ppm
N: 33,5ppm
P: 8.7ppm
K: 19.65 ppm

Stock solution is made with tap water.
I hope I am not doing something terribly wrong with the maths.

So, all of my cards are on the table. Do you see anything wrong here?

 

[parotet]

If I'm not wrong your tap water in Cyprus is very hard... Thus making your micro stock solutions with it is a bad idea unless you use specific chelators.

Jordi

 

[Marcel G]

I doubt you need such a high concentration of phosphates in your tank which is not fully planted. If you have no critters in there, then you can experiment, but hardly anyone is using such a high PO4 (maybe except T.Barr). Also some plants may do better with nutrient-rich substrate. I would rather invest into some quality nutrient-rich substrate than trying to increase nutrient levels in water column (this is not good for critters, it's just good for algae).

 

[ian_m]

Thus making your micro stock solutions with it is a bad idea unless you use specific chelators.

Or use cooled boiled water. Though not seen micro precipitate some people have with their hard water, mine is 22 degree hardness which is F'ing hard on hardness scale.

Where is your Mg coming from ? (don't tell me your tap water....wrong ). Some of these symptoms could be attributed to Mg deficiency, though generally mechanical damage points to CO2 issues.

 

[parotet]

I also agree with Marcel, too much phosphates for such a low plant biomass. I would say too much nutrients actually. My very hard tank water combined with hard EI dosing meant BBA. It improved dosing leaner (but had enriched substrate) and reducing hardness. With both changes TDS went from +1000 microS to max 500 microS. Now it's my reference value

Jordi

 

[Christos Ioannou]

If I'm not wrong your tap water in Cyprus is very hard... Thus making your micro stock solutions with it is a bad idea unless you use specific chelators.
Jordi

Redone micro solution with DI water.

I doubt you need such a high concentration of phosphates in your tank which is not fully planted. If you have no critters in there, then you can experiment, but hardly anyone is using such a high PO4 (maybe except T.Barr). Also some plants may do better with nutrient-rich substrate. I would rather invest into some quality nutrient-rich substrate than trying to increase nutrient levels in water column (this is not good for critters, it's just good for algae).

When something goes wrong you try to grasp from any advice you come across. This is why I doubled the KH2PO4 dosage. Next batch will be only be 3,5g in 700ml to dose 50ml = 1ppm (x3 = 3ppm per week).

About molar clay, well this was supposed to be indispensable given its characteristics (high cec, etc). I don't think I will be ever trying it again - its so hard to plant to begin with and apparently plants are way better off with nutrient rich substrate. I tried to use the enrich it with osmocote root tabs - no dramatic results.

Where is your Mg coming from ? (don't tell me your tap water....wrong ). Some of these symptoms could be attributed to Mg deficiency, though generally mechanical damage points to CO2 issues.

When I started out I was not dosing any Mg since hard water is supposed to contain that... Then, it was time to experiment and so I started adding Mg. Its been a while since I added any. I can alter my batch and add 85g Magnesium Sulphate 7H20 in 700ml solution. Each 50 ml dose will yeld 3.3ppm, summing up 10ppm of Mg / week

How about the pink A.Reinekkii leafs? Anything obvious here? Or is it the CO2 to blame? I have a spare powerhead I can use to improve circulation. Place it somewhere parallel to the spraybar jets. What do you think?