Frustrated with Iron....

[wseaton]

After spending years in saltwater and mostly SPS tanks I decided 6months ago to move over to fresh. I had thriving SPS tanks, and spent considerable amounts of down dialing in dosing and nutrient levels to the point I could set up a tank in a plastic bucket. I'm got to the point I can look at SPS corals in somebody's tank and tell by node shape what their pH levels are.

I thought freshwater planted would be easier and get me out of testing hell, but it's not. I set up a 20L a few months ago, and went full CO2. Initially I had fantastic growth from stem feeders, and then everything slowed down. Blindly dosing ferts fixed the issue to a point, but then resulted in horrendous algae. Cut back all the plants and started slower, and armed myself with testing kits. We gonna do this right this time - just like learning SPS.

What I've narrowed down the problem to (I think) is iron. Alternanthera refused to grown in my tank and even frogbit rolled over and died. Nitrate and Phosphate are fine, but I just recently started testing for iron with a Seachem kit and it was '0'. Added some Seachem Iron and within days saw immediate improvement in Alternanthera and Frogbit. The problem is all we all know iron gluconate is very unstable, and there are pages of threads on the topic of what form of iron people use.

At this point I'm confused as to the best way to proceed, other than keep dosing iron gluconate, but on a daily basis at low levels. That's fine...if it's what I got to do.

What I don't get is how some people can have massive planted tanks, don't dose iron and have no issues. Is there some magical Iron fairy that comes at night and doses their tank?

 

[tam]

What I don't get is how some people can have massive planted tanks, don't dose iron and have no issues. Is there some magical Iron fairy that comes at night and doses their tank?

Shhhh, don't talk about the magical iron fairy or she won't visit you!

Daily dosing is fairly common (split the weekly dose on the bottle by 7) - an autodoser can make that easier.

 

[wseaton]

Autodoser...yes. Still have mine from my SPS tanks. Never thought I would use it on fresh.
Just checked my phosphate level and it was non detectable, so I stand corrected on that. Phosphate was a BIG deal for reef keeping and it had to be nailed in the zone but never figured it for fresh. If it bottoms out in my panted tank I start to see it with things like Ludwigia and hydros immediately.

I'm assuming this is exasperated by CO2 (??). I don't get these glow tech guys with jungle tanks and just toss ferts in them now and then and don't care.

 

[Zeus.]

Unlike you reef folk, we dont advise testing for nutrients, we watch our plants and dose ferts to suit, if something is lacking we dose a bit more.
If your plants was growing well they may have exhausted the nutrients in the substrate also.
How much Fe are you dosing and what type, plus are you using tap water/RO or a blend of both?

 

[Hanuman]

I think it's pretty difficult to advise considering you provided so little information on your tank. Perhaps a picture could also help.

Your problem might actually not even be iron.

 

[dw1305]

Hi all,

What I've narrowed down the problem to (I think) is iron.

Have a look at <"What is the “Duckweed Index” all about?">.

I think it's pretty difficult to advise considering you provided so little information on your tank. Perhaps a picture could also help.

Iron (Fe) deficiency is easy to diagnose from a photo.

Nitrate and Phosphate are fine, but I just recently started testing for iron with a Seachem kit and it was '0'.

we dont advise testing for nutrients, we watch our plants and dose ferts to suit,

Just call it a "bioassay" if it doesn't seem very scientific. Freshwater doesn't have a datum value in the way that marine does, and it makes water testing lot more problematic.

cheers Darrel

 

[wseaton]

Having been involved in FW and SW since the 80s when I set up my first african cichlid breeding tank I'm having trouble processing a lot of these responses. I've only recently jumped into planted, but utterly staggered at the lack of technical depth, unlike SW.

The biggest problem with SW is people understanding that they simply cannot maintain a thriving tank of SPS or even some LPS in a small tank that has no volumetric buffering ability and hence can't stabilize pH and alk. It's physically impossible. Hence why I resorted to extreme out of the box solutions like using sodium hydroxide for alkalinity. Worked.....toxic....but worked staggeringly well. No water change in 2 years either.

The main and only relevant difference between FW planted and SW (where zooxanthellae are the 'plants') is with freshwater plants they don't derive carbon from alk /carbonate sources. Everything else is the same. This is why tank volume is not an issue in FW like it is with SW.

A couple questions directed at me in this thread are also highly annoying. 'Do you use tap or RO?'. RO water within practical assumption can be assumed to be a constant . If I use tap, it's not a constant and nothing can be assumed. Being in the states tap / well water varies in the extreme in terms or calcium carbonate, iron, silicate, etc. Seattle city water is not my water. So, I'm being asked to provide something which is not a constant so what good is it? FWIW, I try to keep my GH below 100 which keeps kH in the 3-4 range with CO2 injection given from what I've read high kH values can screw with iron and nutrient uptake, so I hedge for kH / GH levels in that range. Can go lower if advised.

I've burned through all the posts on this topic and there are very concise and accurate measurements of pH, alk , GH etc., so stating there is no 'datum value' is entirely false. I've seen amazing planted tanks at my local FW store.....using pretty expensive Apex controllers and precise dosing and electronic measurement of params. I don't want to go that route because I've been there with SW.

The links you suggested contain a lot of conjecture and theory and then some pictures of plants. Doesn't work for me. When I added iron gluconate I got an immediate growth response in various plants I've been struggling with and was hoping for more discussion on that - not gatekeeping. No need to discuss further.

IMO, my running theory on iron problems is it's caused by variables in the initial composition of soil used in tanks. Once again, it's assumed soil is a constant when it's not. All kids of metals and minerals contaminate it depending on sourcing. A soil that's initially composed of iron bound compounds based on material sourcing or what area of the farm the shovel was working that day is likely causing the discrepencies. Problem is, you guys don't want to test for it, just stick your finger in the water and lick it 😎

 

[dw1305]

Hi all,

Having been involved in FW and SW since the 80s when I set up my first african cichlid breeding tank I'm having trouble processing a lot of these responses. I've only recently jumped into planted, but utterly staggered at the lack of technical depth, unlike SW.

You are entirely entitled to your opinion, but I don't think you can really complain about lack of technical depth on this forum. We've made efforts to <"talk to scientists">, who are experts in their field, and referenced <"scientific articles"> wherever we can.

Freshwater is much more <"shades of grey"> than a reef aquarium.

The biggest problem with SW is people understanding that they simply cannot maintain a thriving tank of SPS or even some LPS in a small tank that has no volumetric buffering ability and hence can't stabilize pH and alk. It's physically impossible.

It is back to the known datum values for water chemistry, and long term stability, of the oceans. The nearest we have to marine is <"Lake Tanganyika">, and that is very different from <"the Rio Negro"> etc.

The main and only relevant difference between FW planted and SW (where zooxanthellae are the 'plants') is with freshwater plants they don't derive carbon from alk /carbonate sources. Everything else is the same. This is why tank volume is not an issue in FW like it is with SW.

I'm a botanist by training, and it would be fair to say they are some "interesting" observations <"https://www.int-res.com/articles/meps/195/m195p093.pdf">, but some freshwater plants can utilise bicarbonate (HCO3-) as <"their DIC source"> and some can't <"https://www.sciencedirect.com/science/article/abs/pii/S0098847221001507">.

We also may have some <"photosynthetic Cnidarians"> in our tanks, usually one people don't want.

A couple questions directed at me in this thread are also highly annoying. 'Do you use tap or RO?'. RO water within practical assumption can be assumed to be a constant . If I use tap, it's not a constant and nothing can be assumed. Being in the states tap / well water varies in the extreme in terms or calcium carbonate, iron, silicate, etc. Seattle city water is not my water. So, I'm being asked to provide something which is not a constant so what good is it? FWIW, I try to keep my GH below 100 which keeps kH in the 3-4 range with CO2 injection given from what I've read high kH values can screw with iron and nutrient uptake, so I hedge for kH / GH levels in that range. Can go lower if advised.

Harder, more alkaline, water can interfere with the uptake of some nutrients, iron (Fe) being the most frequent.

I've burned through all the posts on this topic and there are very concise and accurate measurements of pH, alk , GH etc., so stating there is no 'datum value' is entirely false. I've seen amazing planted tanks at my local FW store.....using pretty expensive Apex controllers and precise dosing and electronic measurement of params. I don't want to go that route because I've been there with SW.

What is your datum? Our tap water is from a deep limestone (CaCO3) aquifer and a pretty consistent 17 dKH & 17 dGH, but it is very different from the rainwater I use in the tank.

The links you suggested contain a lot of conjecture and theory and then some pictures of plants. Doesn't work for me.

Point taken. For me a picture is worth a thousand words, I know it isn't the same for everyone.

When I added iron gluconate I got an immediate growth response in various plants I've been struggling with and was hoping for more discussion on that - not gatekeeping. No need to discuss further.

If you got an immediate growth response from the plants it is unlikely to be a direct iron response, purely because iron isn't mobile within the plant.

IMO, my running theory on iron problems is it's caused by variables in the initial composition of soil used in tanks.

We don't know what is <"happening in the substrate"> - <"Maq's Substrate Experiment">

Once again, it's assumed soil is a constant when it's not. All kids of metals and minerals contaminate it depending on sourcing. A soil that's initially composed of iron bound compounds based on material sourcing or what area of the farm the shovel was working that day is likely causing the discrepencies.

This is why some of us use a silica sand, or similar, as a substrate.

Problem is, you guys don't want to test for it.

You can test for iron reasonably easily titrimetrically, because it forms a lot of <"insoluble coloured compounds">. You can also use ICP <"or similar">. The problem is just keeping iron ions in solution.

The advantage of a bioassay "using leaf colour" is that the plants will tell you exactly when iron stops being available, and if, and when it becomes available again.

You won't find an analytical test that does that.

Cheers Darrel

 

[Zeus.]

@wseaton all the questions asked by all so far are relevant to help diagnose your issue with the greatest speed/ese and lowest cost, without the need for any test kits.
One full tank picture posted can help diagnose a multitude of potential issues, just like the water your using. Further questions may also be asked about hardware pH stability and so on based on a pic and a few answers
Your call

 

[ElleDee]

Might as well get this out of the way - if you are certain your problem is iron, pick the chelate that is stable in the pH water you have and add that. It will hang around a lot longer than iron gluconate for sure.

You sound frustrated, and I encourage you to stop trying to match things to your SW experience. I'm sure there is some cross over, but at the moment it's giving you some unhelpful expectations.

A couple questions directed at me in this thread are also highly annoying. 'Do you use tap or RO?'. RO water within practical assumption can be assumed to be a constant . If I use tap, it's not a constant and nothing can be assumed. Being in the states tap / well water varies in the extreme in terms or calcium carbonate, iron, silicate, etc. Seattle city water is not my water. So, I'm being asked to provide something which is not a constant so what good is it?

The question is asked because some people use RO and some people don't. You understand the advantages of RO, but plenty of people get by with their tap water. I am blessed with soft tap water, which I can get information about in my local water report and verify with the tests I have. I'm sure there are some fluctuations over time, but nothing that makes a difference in the grand scheme, I promise. As a forum, we try to help people where they are at, even if they have tricky water.

I've burned through all the posts on this topic and there are very concise and accurate measurements of pH, alk , GH etc., so stating there is no 'datum value' is entirely false. I've seen amazing planted tanks at my local FW store.....using pretty expensive Apex controllers and precise dosing and electronic measurement of params. I don't want to go that route because I've been there with SW.

All those bell and whistles are not mandatory for having a fantastic planted tank, they are for convenience. (And in a store setting, as a demonstration of their pricy controller systems.)

Unfortunately, there is no one magical set of parameters that lead to success; it's more about getting all of your tank variables in balance with each other and then keeping them consistent over time. Truly, people take wildly different approaches based on their goals, preferences, budget, free time, etc. There may be some commonalities between tanks, but there are few if any universalities. This is why we ask you to give us a bunch of information about your specific set up, because so much of it is context dependent. At any rate, testing is a minor thing for most people, especially once they figure out what they are doing.

I promise you the people here would be happy to get into the weeds with you about any aspect of your tank, but we need to start with the full picture in order to give useful advice.

IMO, my running theory on iron problems is it's caused by variables in the initial composition of soil used in tanks. Once again, it's assumed soil is a constant when it's not. All kids of metals and minerals contaminate it depending on sourcing. A soil that's initially composed of iron bound compounds based on material sourcing or what area of the farm the shovel was working that day is likely causing the discrepencies. Problem is, you guys don't want to test for it, just stick your finger in the water and lick it 😎

The main issue with iron is that it forms insoluble precipitates easily and ionic iron is only available to plants in one oxidation state. It's easy to get tons of iron into the tank (in the substrate, water column dosing, whatever), it's getting it to stick around in a usable form that's the trick.

 

[Andy Pierce]

At this point I'm confused as to the best way to proceed, other than keep dosing iron gluconate, but on a daily basis at low levels. That's fine...if it's what I got to do.

Since you are injecting CO2 you could start with EI fert dosing which will take care of most of your major problems - note that EI dosing requires weekly 50% water changes which with your setup should be pretty easy to implement. EDTA-chelated iron is a more common approach than iron gluconate and for CO2-injected tanks is usually fine - the CO2 injection keeps the pH in a range where the EDTA-chelated iron is stable enough to do what needs to be done. For "full CO2" most people here in the FW world would interpret that as 30 ppm CO2... is that what you're doing? There are lots of ways of addressing 'horrendous algae', but these are mostly contingent upon what type of algae is the problem - green spot algae indicates a different underlying cause than black beard algae for example. I'm not surprised you're finding it challenging at first - a CO2 injected high light system will be full-on plant metabolism where the 20L volume means small changes can very rapidly get away on you - bigger tanks are usually considered easier than smaller for this reason. You don't mention livestock in your FW tank, but what livestock you have (fish, snails, shrimp) can also significantly impact plant health. Is your tank heated and/or covered? Particularly if both heated and uncovered there will be significant evaporation between water changes which will also shift the water parameters around.

In terms of getting out of testing hell, I expect that will be pretty straightforward. I don't test for anything (except alkalinity for funzies because I'm interested in the chemistry) and very little or no testing at all seems a common approach at least on this forum. Lots of people like the duckweed index although I haven't really found that necessary with EI dosing (which is the whole point of EI dosing).

 

[LFNfan]

Just as a comparator, I have a 70L low tech tank. Fine gravel substrate (1-2mm dia).

• Weekly water change 35L RO plus epsom salts and gypsum targeting 5GH.
• I am dosing 5.5 ppm NO3 weekly with Solufeed 2:1:4, and Solufeed Sodium free TEC for micros targeting 0.5ppm Fe. No additional Fe top-ups. Weekly dose split into four macros, and three micros across the week.
• Ca:Mg:K ratio of 5:3:1 molar.

I have anubias, some stems (limnophila primarily) and a variety of floating plants. And epipremnum, spider plant, monstera obliqua with 'wet roots'.

If you are looking for more precision in establishing and tuning your ferts regime, maybe the IFC ferts calculator available on this forum could be a helpful tool for you.

 

[Hanuman]

If you were concerned about providing a picture, the following information would have helped instead of feeling annoyed by question directed to you:

• Tank age;
• Soil/substrate type used;
• TAP or RO. If TAP then provide your water city/area report. If RO, did you remineralize your water and to what levels?;
• Water dKH/alkalinity value;
• Light duration and intensity;
• How much CO2 (full CO2 doesn't mean anything). What was the PH drop between injection period and non-injection period? Was it stable day after day?;
• Fert regime and PPM values of all macros and micros you've added on a weekly basis;
• Weekly water change volume;
• List of plants.

I could go on but the truth is the above would probably have sufficed to diagnose your issue, ofc, if you were willing to open up, else I don't see how anyone could help in any meaningfull way.

Also for your information not all plants behave the same. Most plants are quite resiliant to changes but some could be in an overall favorable environment to their development, yet uprooting or cutting them harshly or having CO2 or other variables suddenly swing can upset them badly. Did you know that Alternanthera is one of them and gets upset in new tanks/when planted or moved? That plant requires stability and a mature tank to thrive. It's not a difficult plant but not an easy one either. Also a 20L tank is considered very small and it is easy for certain parameters to swing rapidly, temperature being one among others. This can lead to CO2 and O2 dissolution swings and subsequent problems which will affect plants' growth specially when you went "full CO2", whatever that means.

Your iron theory is just one among other potential ones. Iron is a micro nutrient. Micro deficiencies are notoriously difficult to diagnose because usually it's more of a combination of deficiencies and other problematic parameters rather than one single element missing. Yet, in general, iron deficiency usually shows through new leaves being pale/whitish. Did you notice this in your plants? This is the theory. Unless you used a substrate with known to be missing iron and you did not dose any iron, your plants dying might not be because of an iron deficiency alone but a combination of other factors, not iron alone. It's true that the picture of what looks to be an Alternanthera on the Seachem iron bottle can be convincing though!

Since you seem to know what your issue is, iron that is, then I wonder why posting at all here in the first place. You are new to this forum as well as to FW planted tanks. The usual approach is to remain humble and let people with experience and expertize help rather than alienating them. Your experience in SW tanks is great but will only so much transpose to FW. Despite what you think, these are 2 distinct worlds.

 

[ElleDee]

Your iron theory is just one among other potential ones. Iron is a micro nutrient. Micro deficiencies are notoriously difficult to diagnose because usually it's more of a combination of deficiencies and other problematic parameters rather than one single element missing.

I'd take that further and say that many plant issues are tricky to work out, especially for new people. There's a tendency to assume the problem is nutrition, but there are so many other things that lead to stunted growth and algae. Starting with full tank information can stop us from barking up the wrong tree.

But you're right, deficiencies are particularly misleading. If you look on the internet you can find charts that explain the differences between them and it seems so straightforward, but the reality is something else. Deficiencies don't manifest exactly the same way in every plant, which is why having the Duckweed (Frogbit) Index is helpful - it gives us a standard.

 

[Hanuman]

But you're right, deficiencies are particularly misleading. If you look on the internet you can find charts that explain the differences between them and it seems so straightforward, but the reality is something else. Deficiencies don't manifest exactly the same way in every plant, which is why having the Duckweed (Frogbit) Index is helpful - it gives us a standard.

@dw1305 Can elaborate on this better than I can, but I beleive deficiencies are "easier" to diagnose on terrestrial plants.

 

[Zeus.]

I'd take that further and say that many plant issues are tricky to work out, especially for new people. There's a tendency to assume the problem is nutrition, but there are so many other things that lead to stunted growth and algae. Starting with full tank information can stop us from barking up the wrong tree.

But you're right, deficiencies are particularly misleading. If you look on the internet you can find charts that explain the differences between them and it seems so straightforward, but the reality is something else. Deficiencies don't manifest exactly the same way in every plant, which is why having the Duckweed (Frogbit) Index is helpful - it gives us a standard.

deficiencies are "easier" to diagnose on terrestrial plants.

Plus the deficiency can be a side effect of the real issue esp in a CO2 injected tank, where growth is increased to the extra abundance of Carbon. Most deficiencies in CO2 injected tanks are due to poor implementation of the CO2 injection, with fluctuating [CO2] esp during the first 4 to 5hrs of the photo period. Many issues can be solved with better flow/tank turnover which revolves the issue of the diffusion rate of CO2 in water being 10,000 slower than in air. Which IMO is why deficiencies are "easier" to diagnose on terrestrial plants as [CO2] is relatively stable in air.

To quote our Guru of [CO2] @ceg4048 Flow is King of the CO2 injected tank, once flow is good enough to suit the lights and biomass of plants stable localised [CO2] is easier to achieve once a pH profile has been done.

The flow needed to achieve success varies from tank to tank

 

[John q]

You do know iron is a micro nutrient,? We don't need to add much. Suspect the opp is falling into the trap of Fe deficiency 🤠

 

[dw1305]

Hi all,

@dw1305 Can elaborate on this better than I can, but I beleive deficiencies are "easier" to diagnose on terrestrial plants.

It is mainly that CO2 is <"freely available to terrestrial plants">, which takes <"one variable out of the equation">.

Nutrient deficiency can potentially show up more rapidly in aquatic plants, because they grow in a much denser medium, meaning that they don't need to allocate as much <"carbohydrate to structural support">.

Cheers Darrel

 

[Happi]

What I've narrowed down the problem to (I think) is iron. Alternanthera refused to grown in my tank and even frogbit rolled over and died. Nitrate and Phosphate are fine, but I just recently started testing for iron with a Seachem kit and it was '0'. Added some Seachem Iron and within days saw immediate improvement in Alternanthera and Frogbit. The problem is all we all know iron gluconate is very unstable, and there are pages of threads on the topic of what form of iron people use.

At this point I'm confused as to the best way to proceed, other than keep dosing iron gluconate, but on a daily basis at low levels. That's fine...if it's what I got to do.

Iron Gluconate, while it may be unstable, but it is preferred form of Iron (Fe2) for the aquatic plant. you can always expect quick results from it if you are truly deficient on Iron. Fe3 Iron (EDTA, DTPA etc.) on the other hand may require plant to use more energy to extract Iron. Iron is also more available in Acidic environment vs Alkaline environment. if you use acidic soil and maintain low PH, most of the nutrient related issues are resolved. Iron is unique though, its availability is highly influenced by several factors, PH is one of the major factor. other factors to consider is Mn and Mg which also play important role here, Deficiency in both can look like Iron Deficiency. excessive Phosphate in the water can be a major problem for Iron as well. this is bit controversial but there are some scenarios where person can be dealing with nutrients deficiencies which are actually toxicities caused by different nutrients. for example:
you can see how plant can appear to look deficient of something (Fe, Mn, Mg) when all three are present in excess amount "Very High Traces, High Dosing, plant damage, PAR 80-100"

if this issues is resolved by adding Iron Gluconate, that would suggest that whatever other source of Iron you are adding isn't available to the plants.

What I don't get is how some people can have massive planted tanks, don't dose iron and have no issues. Is there some magical Iron fairy that comes at night and doses their tank?

in most cases Iron is already present in their tap water or substrate. the need for Iron is actually not that high, its quite low, but its availability is usually the problem due to the above reasons.

see these references:
Plant deficiencies and the Fe Experiment
Consistency Deficiency
My 60p soft water
Solufeed 2:1:4 and Solufeed Sodium Free TEC or Solufeed Coir TEC Combination