Plant deficiencies and the Fe Experiment

[KirstyF]

As some of you may know, following a chlorosis issue, I’ve been running a number of dosing tests in my tank.

These have been centred primarily on Fe, and specific to chlorosis, in my hardwater tank, but I’ve put plant deficiencies in the thread title as I’m more than happy to open the thread to any other types of deficiencies that people may wish to discuss and am also very interested to hear other people’s experiences or contributions in regard to this subject matter.

I should also note that chlorosis can be caused by other nutrient deficiencies so Fe is not always the answer.

Background info for Fe:
Fe EDTA - stable up to Ph 6.3
Fe DTPA - stable up to Ph 7
Fe EDDHA - Stable up to Ph 9
Fe Gluconate - unchelated so will only be available for a short period in hard water/higher Ph environment.

Note: All dosing changes were run for a minimum of 3 weeks (sometimes more) to monitor response.

I’ll start with my tank parameters:

700l High Tech with 12 x flow on paper; in reality somewhat less. (2 x Oase 850 thermo - 2x Maxspect gyres)

Gh/KH estimated at 10-12 (KH not available on my water report but estimates supported by Darrel’s, @dw1305 , knowledge of geology)

Ph - tap 7.6 - The ph in the tank sits at a steady 6.6 after Co2, and I believe rarely gets above 7.2

Macro Dosing
No3 - 20-30ppm from tap - no additional dosing
Po4 - now 6ppm but just 2ppm at outset of this trial
K - now 15ppm but around 7ppm at outset of this trial
Mg - 10ppm
Macros frontloaded

Micro Dosing (at outset of trial)
My micros used to be up to 5x the dosing below (depending on nutrient) but seeing friends here with much leaner micros, I wanted to see results of a reduction.

Fe (DTPA 8%) 0.1ppm
Mn 0.15 ppm (this was originally 0.1ppm but was increased shortly after chlorosis set in, to exclude it as a cause)
B 0.02ppm
Mo 0.005ppm
Zn 0.02ppm
Cu 0.006ppm
Micros dosed 3xpw

Perhaps unsurprisingly, in my hard water, the result of Fe at 0.1ppm was a pretty rapid onset of chlorosis. Note however that we have colleagues successfully running beautiful soft water tanks at that level.

First fix was to up the DTPA to 0.3ppm - no improvement

Second fix was to try DTPA at 0.1ppm plus EDDHA at 0.2ppm to maintain a 0.3ppm total - no improvement

3rd fix was DTPA at 0.15ppm (in the macro solution) plus what I thought was 0.1ppm of Fe gluconate, dosed on opposite days to the Micro
I have since had it pointed out that Seachem bottle instructions are a little misleading and this dose was actually 0.25ppm. I clearly wasn’t paying attention there 🤪 so total dose was actually 0.4ppm - almost immediate and dramatic improvement

It was at this point that I increased P&K, as noted above, as I had some long term, minor but fairly annoying GSA on slow growers. (Way prior to the chlorosis issue) This worked out pretty well too but that’s another story.

So, next move was to add the gluconate dose into the micro mix, rather than dosing separately to see if it responded differently. Difficult to tell if there was much difference - greens possibly slightly less bright.

I now wanted to test ‘Fe only’ to establish how much benefit may still be being derived from that part dose of DTPA or whether the impact was all about the gluconate, but to do that, I needed to induce chlorosis again.

Moved back to 0.3ppm DTPA/no gluconate - early signs of chlorosis apparent within 3 weeks.

0.3ppm of Fe gluconate only is being tested right now and results are to follow. If results are good, I then plan to reduce incrementally to establish the level at which it starts to fail.

I also still want to do some further comparison tests between daily and 3xpw dosing and also exactly what dosage/frequency of ‘DTPA/EDDHA only’ will match the results of gluconate, so this will be ongoing for a while yet.

We may get to something like…X ppm of Fe gluconate dosed at X frequency delivers the optimum response….or ultimately we may conclude otherwise but…..we’ll see.

What does this tell us so far….

0.3ppm of DTPA Fe is not enough for my tank. I feel it kinda should be……0.5ppm is max EI level which is designed to be well over what any tank could ever need based on Uber lights and hungry stems….and mine is middling light and mixed planting. Equally there are others using those higher levels and still struggling….and, tbf, clearly some who aren’t.

EDDHA is maybe not the answer either.
(A bit more testing on ‘EDDHA only’ is needed)

Possibly that an entirely unchelated Fe solution, may actually be super helpful in a hard water environment (despite this being counterintuitive) The hypothesis being that, as this product is already in the form that the plants require, it can be rapidly taken up despite limited availability time. Note: My dosing takes place about 1hr into photoperiod when the plants are ready to suck it in. Dose 1hr before lights kick in and it would likely be largely gone by the time the plants wanted it.

Also that I appear to have suffered no detriment or deficiency from the reduction in all of the other micros that I was previously using, which seems to evidence that I certainly didn’t need those levels.

I think it’s too early to conclude any more than that right now but welcome input/data/photos etc for further discussion.

I will collate and store anything that comes in so please add detail particularly regarding ppm’s and Ph levels, and I’ll continue to update with test results. Happy to take suggestions on testing parameters too. 😊

Over to you folks.

 

[KirstyF]

Hi @keef321
Don’t suppose you could do a ‘copy and paste’ of your other post over onto this thread….or at least a brief description and that rather cool helferi pic. We can then pick up where we left off as such. 😊

 

[xZaiox]

A fantastic thread @KirstyF - you have clear evidence that gluconate is working in your tank where the chelates have failed. It's especially interesting that your tank is hard water, given the typical (and logical) advice is that chelates will perform better due to sticking around longer, yet it turns out that gluconate (which is likely to precipitate in hard water) effectively fixes your problem.

I'm currently experimenting with this in my hard water tank also (20 dGH, 10 dKH), and I will hopefully have some further input to give in a few weeks time.

 

[keef321]

Hi @keef321
Don’t suppose you could do a ‘copy and paste’ of your other post over onto this thread….or at least a brief description and that rather cool helferi pic. We can then pick up where we left off as such. 😊

Happy yo add to the thread Kirsty

I too have problem with Hard water & high PH. I’m currently Dosing TNC heavily together with DTPA iron. Recently I have started to ensure I only dose when the PH has dropped due to Co2 injection, and dose iron on alternative days to my TNC. This has given me the best results so far. I think when my PH rises with gas off over night any iron is gone. I am looking at trialling some of this EDDHA Iron Plus B to see if this improves things. I have to dose a lot of DTPA to see improvement, therefore think EDDHA may help.
If I don’t dose Iron every day I see deficiencies within the week, and it’s very extreme (totally white leaves).

My GH is 13, KH 10, PH before gas 7.6 (degassed 8.0-8.1), after gas 6.8-6.9. Currently dosing N:18,P:2.4,K:60,Mg:9.6,Fe EDTA 0.96 & 1ppm DTPA per week. The Fe EDTA looks a high figure, but I know this is not available to the plants, as can be seen in the photo when I stop dosing DTPA. I know the K Potassium levels look high, but this is simply how the TNC mix is (and I am aiming for EI levels), and as I have found, the more I dose, the less algae I get 😀

Photo of Pogostemon Helferi after stoping dosing DTPA for a week, then starting again.

Interestingly DW1305 reports that Pogostemon Helferi is a frequent contributor to FE deficiency threads here on UKAPS, together with Rotala Rotundifolia. I had huge problems with Rotala Rotundifolia with lots of stunted growth, and generally weak plants. I would like to try growing it again once I am happy knowing my plants are getting their full fill of iron.

 

[LMuhlen]

Note: My dosing takes place about 1hr into photoperiod when the plants are ready to suck it in. Dose 1hr before lights kick in and it would likely be largely gone by the time the plants wanted it.

This is something that sounds intuitive, but that I wouldn't trust to be entirely true. My basic understanding of plant internal shenanigans is that they have some ways to keep a short time reserve of nutrients through their transportation mechanisms. Even with Fe being a fixed non-moving nutrient, I understand that as meaning that once it has been used it stays there, but up to that point it gets transported to the right place. Otherwise there couldn't be absorption through the roots. Also, the plants seem to grow at night using the sugars they produce during the day.

I'm personally struggling with Fe in my tanks, or at least I think I am because there may be many concomitant issues and it has been hard to isolate a main factor as you did. In any case, I'm now using EDDHA, have been for a few months, but I'm not seeing the improvement that I expected, so I'll probably shift to gluconate again soon to see what changes. No DTPA available around here for whatever reason.

I'm curious about using simple Iron citrate or sulphate. I think @_Maq_ does that? Although his approach is overall very different than most in regards to his complete control over what goes in his test tanks, and also with not using CO2.

 

[keef321]

As some of you may know, following a chlorosis issue, I’ve been running a number of dosing tests in my tank.

These have been centred primarily on Fe, and specific to chlorosis, in my hardwater tank, but I’ve put plant deficiencies in the thread title as I’m more than happy to open the thread to any other types of deficiencies that people may wish to discuss and am also very interested to hear other people’s experiences or contributions in regard to this subject matter.

I should also note that chlorosis can be caused by other nutrient deficiencies so Fe is not always the answer.

Background info for Fe:
Fe EDTA - stable up to Ph 6.3
Fe DTPA - stable up to Ph 7
Fe EDDHA - Stable up to Ph 9
Fe Gluconate - unchelated so will only be available for a short period in hard water/higher Ph environment.

Note: All dosing changes were run for a minimum of 3 weeks (sometimes more) to monitor response.

I’ll start with my tank parameters:

700l High Tech with 12 x flow on paper; in reality somewhat less. (2 x Oase 850 thermo - 2x Maxspect gyres)

Gh/KH estimated at 10-12 (KH not available on my water report but estimates supported by Darrel’s, @dw1305 , knowledge of geology)

Ph - tap 7.6 - The ph in the tank sits at a steady 6.6 after Co2, and I believe rarely gets above 7.2

Macro Dosing
No3 - 20-30ppm from tap - no additional dosing
Po4 - now 6ppm but just 2ppm at outset of this trial
K - now 15ppm but around 7ppm at outset of this trial
Mg - 10ppm
Macros frontloaded

Micro Dosing (at outset of trial)
My micros used to be up to 5x the dosing below (depending on nutrient) but seeing friends here with much leaner micros, I wanted to see results of a reduction.

Fe (DTPA 8%) 0.1ppm
Mn 0.15 ppm (this was originally 0.1ppm but was increased shortly after chlorosis set in, to exclude it as a cause)
B 0.02ppm
Mo 0.005ppm
Zn 0.02ppm
Cu 0.006ppm
Micros dosed 3xpw

Perhaps unsurprisingly, in my hard water, the result of Fe at 0.1ppm was a pretty rapid onset of chlorosis. Note however that we have colleagues successfully running beautiful soft water tanks at that level.
View attachment 199417
View attachment 199418

First fix was to up the DTPA to 0.3ppm - no improvement

Second fix was to try DTPA at 0.1ppm plus EDDHA at 0.2ppm to maintain a 0.3ppm total - no improvement

3rd fix was DTPA at 0.15ppm (in the macro solution) plus what I thought was 0.1ppm of Fe gluconate, dosed on opposite days to the Micro
I have since had it pointed out that Seachem bottle instructions are a little misleading and this dose was actually 0.25ppm. I clearly wasn’t paying attention there 🤪 so total dose was actually 0.4ppm - almost immediate and dramatic improvement
View attachment 199423
View attachment 199424

It was at this point that I increased P&K, as noted above, as I had some long term, minor but fairly annoying GSA on slow growers. (Way prior to the chlorosis issue) This worked out pretty well too but that’s another story.

So, next move was to add the gluconate dose into the micro mix, rather than dosing separately to see if it responded differently. Difficult to tell if there was much difference - greens possibly slightly less bright.

I now wanted to test ‘Fe only’ to establish how much benefit may still be being derived from that part dose of DTPA or whether the impact was all about the gluconate, but to do that, I needed to induce chlorosis again.

Moved back to 0.3ppm DTPA/no gluconate - early signs of chlorosis apparent within 3 weeks.
View attachment 199425View attachment 199426View attachment 199427

0.3ppm of Fe gluconate only is being tested right now and results are to follow. If results are good, I then plan to reduce incrementally to establish the level at which it starts to fail.

I also still want to do some further comparison tests between daily and 3xpw dosing and also exactly what dosage/frequency of ‘DTPA/EDDHA only’ will match the results of gluconate, so this will be ongoing for a while yet.

We may get to something like…X ppm of Fe gluconate dosed at X frequency delivers the optimum response….or ultimately we may conclude otherwise but…..we’ll see.

What does this tell us so far….

0.3ppm of DTPA Fe is not enough for my tank. I feel it kinda should be……0.5ppm is max EI level which is designed to be well over what any tank could ever need based on Uber lights and hungry stems….and mine is middling light and mixed planting. Equally there are others using those higher levels and still struggling….and, tbf, clearly some who aren’t.

EDDHA is maybe not the answer either.
(A bit more testing on ‘EDDHA only’ is needed)

Possibly that an entirely unchelated Fe solution, may actually be super helpful in a hard water environment (despite this being counterintuitive) The hypothesis being that, as this product is already in the form that the plants require, it can be rapidly taken up despite limited availability time. Note: My dosing takes place about 1hr into photoperiod when the plants are ready to suck it in. Dose 1hr before lights kick in and it would likely be largely gone by the time the plants wanted it.

Also that I appear to have suffered no detriment or deficiency from the reduction in all of the other micros that I was previously using, which seems to evidence that I certainly didn’t need those levels.

I think it’s too early to conclude any more than that right now but welcome input/data/photos etc for further discussion.

I will collate and store anything that comes in so please add detail particularly regarding ppm’s and Ph levels, and I’ll continue to update with test results. Happy to take suggestions on testing parameters too. 😊

Over to you folks.

I agree 0.3ppm of DTPA Fe is potentially not enough for you. I have been dosing 1ppm. If you check out some of the threads by Tom Barr regarding Fe (barrreport.com) he suggests a multi-chelator approach (ferrous gluconate, EDTA & DTPA) and dosing 1-2ppm!! So I think you can go much highter. He states he has dosed huge amounts of iron fe and never seen an issue with toxicity.

 

[FISHnLAB]

Thanks for doing this Kristy👍. This is interesting stuff and applicable to refining my main display tank I think. I'm pretty sure I am seeing iron deficiencies even with 1.5X EI daily dosing(likely due to high calcium levels leaching from my seiru stone). I went back to 1X EI dosage and started to add Fe Gluconate to see if that helps. How much Seachem Flourish Iron are you adding per liter in addition to your regular Fe dosing?

 

[Wookii]

The hypothesis being that, as this product is already in the form that the plants require, it can be rapidly taken up despite limited availability time. Note: My dosing takes place about 1hr into photoperiod when the plants are ready to suck it in. Dose 1hr before lights kick in and it would likely be largely gone by the time the plants wanted it.

It's my understanding that plants will take up micros outside of the photo period (@X3NiTH explained that to me and may be able to elaborate). It's also worth bearing in mind that DTPA chelate is broken down rapidly by light, so in a hard water/higher pH tank I would always dose in the dark a little after CO2 has been switched on and the pH lowered sufficiently. I then dose macros a touch before lights on - to give sufficient circulation time around the tank before lights on - so plants have everything they need the minute the light starts to hit them.

I also always dose both micros and macros daily, no reason to dose less if you use an auto-doser - I believe @Zeus. experimented with dosing hourly or similar at one point. Doing that with the addition of DTPA iron along with the EDTA iron in the standard micro mix fixed chlorosis issues for me some years back in my tap water tanks (6dKH, 12dGH), and I've not had it reoccur since with the additional DTPA.

 

[dw1305]

Hi all,

Photo of Pogostemon Helferi after stopping dosing DTPA for a week, then starting again.

That is the real advantage of iron (Fe) as a diagnosable deficiency. Iron isn't mobile within the plant, so the plant leaf tissue gives an indication of iron availability <"at the time of its formation">, and that is <"an indelible mark">.

You can still use the <"Duckweed Index"> to diagnose <"iron deficiencies"> (what do they look like now? @tam ?), but ideally you want the plants <"not to be iron deficient">, because deficiency means that you can't use the <"leaf colour chart"> or <"plant growth rate"> until iron ions are available again.

This was @jameson_uk 's <"iron deficient Frogbit"> (Limnobium laevigatum), showing the same on (green) / off (white) symptoms.

It doesn't matter if iron ions were available before, or after, that time, the pale, chlorotic band (<"or reticulated pattern">) on a leaf is an indicator of lack of iron at that particular moment.

Because it is only really iron deficiency that <"causes chlorosis in new growth"> we don't have too many other options to worry about. Deficiencies of mobile elements are <"much easier to treat">, but much <"more difficult to diagnose">.

cheers Darrel

 

[xZaiox]

I agree 0.3ppm of DTPA Fe is potentially not enough for you. I have been dosing 1ppm. If you check out some of the threads by Tom Barr regarding Fe (barrreport.com) he suggests a multi-chelator approach (ferrous gluconate, EDTA & DTPA) and dosing 1-2ppm!! So I think you can go much highter. He states he has dosed huge amounts of iron fe and never seen an issue with toxicity.

This is interesting to me. I've had chlorotic issues in my hard water tank for a while now, and my last micro mix included: FeDTPA @ 0.5ppm, FeEDDHA @ 0.2ppm, and FeEDDHSA @ 0.3ppm - I thought this seemed like very high dosing, but despite all of this, my hygrophilia polysperma and limnophila hippuridoides show a yellowing/whitening in the new growth only. My frogbit also shows some light paleness. Manganese is also dosed to 0.28ppm, so I'm doubtful it's that.

I've currently switched to dosing 0.2ppm DTPA and 0.5ppm gluconate. I'll be trialling this for a response for the next 2-3 weeks in the hopes I get a response like @KirstyF has, but if no bueno then I might possibly try increasing the chelates even further. I definitely won't be mega-dosing EDDHA though, that stuff really stains the water 😬

 

[KirstyF]

Firstly, thanks everyone for all of the fab input. I’ll respond to some more later, just taking a quick break at work!

This is something that sounds intuitive, but that I wouldn't trust to be entirely true. My basic understanding of plant internal shenanigans is that they have some ways to keep a short time reserve of nutrients through their transportation mechanisms. Even with Fe being a fixed non-moving nutrient, I understand that as meaning that once it has been used it stays there, but up to that point it gets transported to the right place. Otherwise there couldn't be absorption through the roots. Also, the plants seem to grow at night using the sugars they produce during the day.

Yes, I’m also working on the belief that the plants have the ability to transport/store and then utilise nutrients but the purpose of dosing during photoperiod has been an assumption that this is when plants are at optimal uptake. This being more critical if using an Fe source with a short lifespan of availability. (Note the word assumption 😂)

How much EDDHA are you using and what is your Gh/Kh/Ph if you don’t mind me asking.

It's my understanding that plants will take up micros outside of the photo period (@X3NiTH explained that to me and may be able to elaborate). It's also worth bearing in mind that DTPA chelate is broken down rapidly by light, so in a hard water/higher pH tank I would always dose in the dark a little after CO2 has been switched on and the pH lowered sufficiently. I then dose macros a touch before lights on - to give sufficient circulation time around the tank before lights on - so plants have everything they need the minute the light starts to hit them.

I also always dose both micros and macros daily, no reason to dose less if you use an auto-doser - I believe @Zeus. experimented with dosing hourly or similar at one point. Doing that with the addition of DTPA iron along with the EDTA iron in the standard micro mix fixed chlorosis issues for me some years back in my tap water tanks (6dKH, 12dGH), and I've not had it reoccur since with the additional DTPA.

As with the above comment from @LMuhlen , this is interesting, as perhaps my assumptions regarding uptake during photosynthesis are incorrect. 🤔
This is why I love this forum!
It would be great to get some detail on the mechanics of how that works and it’s certainly food for thought.

Could you possibly also confirm the level of DTPA and EDTA that you are dosing (daily and weekly total) and Gh/Kh/Ph too as this is all grist for the mill.

It is helpful to understand at least some basic details of who is doing what and in what parameters. Tank variations mean this is not wholly scientific but I still think useful for our purposes. 😊

 

[keef321]

This is interesting to me. I've had chlorotic issues in my hard water tank for a while now, and my last micro mix included: FeDTPA @ 0.5ppm, FeEDDHA @ 0.2ppm, and FeEDDHSA @ 0.3ppm - I thought this seemed like very high dosing, but despite all of this, my hygrophilia polysperma and limnophila hippuridoides show a yellowing/whitening in the new growth only. My frogbit also shows some light paleness. Manganese is also dosed to 0.28ppm, so I'm doubtful it's that.

I've currently switched to dosing 0.2ppm DTPA and 0.5ppm gluconate. I'll be trialling this for a response for the next 2-3 weeks in the hopes I get a response like @KirstyF has, but if no bueno then I might possibly try increasing the chelates even further. I definitely won't be mega-dosing EDDHA though, that stuff really stains the water 😬

Sounds like a good plan. I have never dosed EDDHA yet, but have read it turns the water pink 🙃

I find DTPA is good up to about 2ppm, when you hit around 3ppm the water starts to yellow.

 

[KirstyF]

Thanks for doing this Kristy👍. This is interesting stuff and applicable to refining my main display tank I think. I'm pretty sure I am seeing iron deficiencies even with 1.5X EI daily dosing(likely due to high calcium levels leaching from my seiru stone). I went back to 1X EI dosage and started to add Fe Gluconate to see if that helps. How much Seachem Flourish Iron are you adding per liter in addition to your regular Fe dosing?

On the latest test I’m adding 7.5ml per dose, 3xpw, in 700ltrs, and only using gluconate. (According to the Seachem calculator, 7.4ml would be precisely 0.1ppm) This is therefore 0.3ppm pw (or close enough) but note that due to short lifespan, there will likely never be more than a single dose available in the tank at any one time.

As mentioned in my first post, the dosing for Seachem Flourish is a little misleading, as it states 5ml per 200ltrs to maintain 0.1ppm, however, if you go onto Seachems dosing calculator it advised that this actually provides 0.25ppm of Fe and if I do a precise calculation, I suddenly get an extra 0.4ml across 700ltrs for a 0.1ppm dose. 🤪

When I saw that first significant improvement, I was dosing DTPA at 0.15ppm pw in my micro, and 5ml of Seachem Flourish, 3 x pw, on opposite days. (Mostly because a 5ml capful was easy.) This equates to between 0.2 and 0.25ppm pw of gluc.

As 5ml across 700ltrs is pants to calculate, If you want to keep it easy, you could just go for 1ml per 100ltrs will give you 0.1ppm (actual) and assume that using that 3 x pw would more than equal what I put in. 🤷‍♂️

Hope that makes sense. 😊

 

[KirstyF]

This is interesting to me. I've had chlorotic issues in my hard water tank for a while now, and my last micro mix included: FeDTPA @ 0.5ppm, FeEDDHA @ 0.2ppm, and FeEDDHSA @ 0.3ppm - I thought this seemed like very high dosing, but despite all of this, my hygrophilia polysperma and limnophila hippuridoides show a yellowing/whitening in the new growth only. My frogbit also shows some light paleness. Manganese is also dosed to 0.28ppm, so I'm doubtful it's that.

I've currently switched to dosing 0.2ppm DTPA and 0.5ppm gluconate. I'll be trialling this for a response for the next 2-3 weeks in the hopes I get a response like @KirstyF has, but if no bueno then I might possibly try increasing the chelates even further. I definitely won't be mega-dosing EDDHA though, that stuff really stains the water 😬

1ppm just feels like it should be more than enough regardless right!!

I’m very much looking forward to seeing your results, 👍

 

[KirstyF]

agree 0.3ppm of DTPA Fe is potentially not enough for you. I have been dosing 1ppm. If you check out some of the threads by Tom Barr regarding Fe (barrreport.com) he suggests a multi-chelator approach (ferrous gluconate, EDTA & DTPA) and dosing 1-2ppm!! So I think you can go much highter. He states he has dosed huge amounts of iron fe and never seen an issue with toxicity.

Another good point, and yet iron toxicity is certainly known to be an issue in soil grown plants and well recorded in rice production where it causes stunting, bronzing of leaves and reduction in yield. Whilst many ‘non aquatic’ issues don’t translate well to our tank environments of course, and ppm’s are on a whole different scale, it would be interesting to see what additional info might be out there about this. 😊

 

[LMuhlen]

How much EDDHA are you using and what is your Gh/Kh/Ph if you don’t mind me asking.

My tank has much softer water, at 0.5dKH and ~6dGH (due to the addition of Ca and Mg salts, tap water is 3dGH). My pH oscillates from 7.0 to 6.0, roughly.

For some reason, I was under the impression that 0.1ppm Fe should be enough and more than that would be an excess for EI strategy purposes. I'm now seeing that this might not be the case. I originally moved from gluconate because I found myself having to add 0.3ppm weekly and thought something was wrong, but maybe it wasn't.

My plan with EDDHA was to add 0.1ppm weekly, I read that at this concentration it should be mostly colorless. But that turned my tank water into tea, it looked like a black water tank. This makes me suspect that there might be something wrong with my EDDHA, but in any case I followed the recommendation I was given to just reduce the dosage up to the point where it is barely visible, and that turned out to be around 2 weekly doses of 0.03ppm, although it is so little powder that there is a wide margin of error.

There is some Fe EDTA added with my macros mix as well, something around 0.05ppm weekly if I remember it right.

As I said, I'm not even sure my issues are due to an iron deficiency, but I had this suspicion based on some plants like Blyxxa japonica and had my floating plants diagnosed as such in this forum, although they weren't just pale, but also damaged from this alleged deficiency.

 

[dw1305]

Hi all,

Another good point, and yet iron toxicity is certainly known to be an issue in soil grown plants and well recorded in rice production where it causes stunting, bronzing of leaves and reduction in yield.

You can definitely have <"too much iron (Fe++(+))">. Plants from naturally acidic and / or anaerobic conditions <"have physiological or morphological adaptations"> to reduce iron toxicity, which is probably one reason why they struggle in alkaline, oxidising environments where the problem is getting iron in, not keeping it out.

cheers Darrel

 

[Mattant1984]

@KirstyF so ive been reading your post and it's great (even if I don't necessarily understand it all 😆) and I do also think I have a slight Iron deficiency in my tank with some yellowing of leaves and extremely slow growing plants (plants that would usually grow quick



As your aware my tank is the same size as yours although low tech and I also live in a hard water area with a ph about 7.6 and kh and gh between 12 and 15

I am dosing Solufeed 2:1:4 at 6g 3 times per week and plants have definitely improved for sure however after looking into the type of iron that Solufeed contains It is EDTA.



After reading what you have written about iron and pH above am I right in thinking this type of iron is only good a ph of 6.3 and below??

 

[KirstyF]

@KirstyF so ive been reading your post and it's great (even if I don't necessarily understand it all 😆) and I do also think I have a slight Iron deficiency in my tank with some yellowing of leaves and extremely slow growing plants (plants that would usually grow quick



As your aware my tank is the same size as yours although low tech and I also live in a hard water area with a ph about 7.6 and kh and gh between 12 and 15

I am dosing Solufeed 2:1:4 at 6g 3 times per week and plants have definitely improved for sure however after looking into the type of iron that Solufeed contains It is EDTA.



After reading what you have written about iron and pH above am I right in thinking this type of iron is only good a ph of 6.3 and below??

The short answer to your question is yes and, particularly as you are low tech, and therefore don’t have a lower Ph period, traditional wisdom would suggest Fe EDDHA as your best solution.

One of the issues with this is that it tends to tint your water pink, so you could try DTPA, or a mix of this and EDDHA.

With a low tech, your plants will likely not be demanding as much Fe as in a high tech situation (where plants are on ‘higher speed’) and it is my experience that hardwater, even in high tech, can result in slower growth than a soft water equivalent. This means that you may generally have slower growth than you might expect and additional Fe will not necessarily speed that up to any great extent. I would suggest that you target healthy growth as your priority and, as long as you are seeing that, don’t worry too much if things take a little longer.

I can tell you that my low tech (which also sits around Ph 7.6) has never really shown a noticeable deficiency when dosed with DTPA, despite the Ph technically being outside its ideal tolerance range. (I have never used EDTA so cannot offer a comparison I’m afraid)

I am now dosing my low tech with gluconate only, in line with the high tech, but as the planting is very simple (Vals, bolbitis, crypts mostly) and therefore very low demand, I am observing my floaters primarily to establish response.

It is entirely possible that low tech tanks, consistently sitting in this Ph range, may not show the same response as in a high tech environment and/or Fe gluconate may not show the same efficacy. Until I’ve spent a little longer throwing gluconate at this tank, I can’t really give you an honest recommendation on it.

The long and the short is that, whilst we can’t guarantee that your issues are Fe related, your Ph level with Fe EDTA could easily make it a candidate. (Some pics of the affected plants may help if you can pop some on for us) If it is the issue, low tech can be a bit more forgiving, so simply using an addition of Fe DTPA may be all you need to solve it.

Bear in mind that, above the stable Ph ranges quoted, the Fe doesn’t just stop working, albeit, it may become less efficient.

Hope that helps but do come back if you’ve any more questions. 😊

 

[Mattant1984]

Many thanks @KirstyF that's a really comprehensive response so much appreciated.

In regards to dosing of the iron is it a once a week thing or do you dose the same time as your other ferts?? Are there any downsides to dosing iron??

I supose its all trial and error really isn't it, just finding that sweet spot