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Iron deficiency and which chelator do I need?

Beaker

Seedling
Joined
24 Aug 2020
Messages
21
Location
Colorado
It is looking like I have an iron deficiency and I am trying to decide which chelator I need. I have a ph of 7.9 when the lights are out and a ph of 6.5 when the lights are on.

I have been dosing DTPA iron after the lights go out and I am dosing .3ppm a week.

I was having an iron deficiency before and I chanced from ETPA to DTPA and it fixed it. Now I am wondering if I need to go to EDDHA or get an RO unit.

Can I dose DTPA when the CO2 is on and the ph is 6.5 or does it not work that way?

(I'm confident that it is a nutrient problem and not a CO2 problem because it is affecting my floating plants)

Is there also a way to keep the dosing lines clean and algae-free?

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Hello,
I would Ideally dose the DTPA before the lights come and when PH is lowest from the addition of CO2. I think DTPA starts degrading around PH7.4
 
Can I dose DTPA when the CO2 is on and the ph is 6.5 or does it not work that way?

Yes you can But Fe DTPA is light sensitive however plants will have their fill in a couple of hours so you should be fine dosing when lights come on and pH is lowest, with a pH of 6.5 you should be fine with EDTA. it is a good idea to blackout the fert dosing line with Fe DTPA in it as it will stop it photo degrading before it lands in the tank.
Is there also a way to keep the dosing lines clean and algae-free?

Yes,
1. Have and air gap between the dosing pipes and the tank water, this will help in many ways and in your pic it seems they are in the water which is a big NO-NO. If they are in the water the lines will need a really good clean or replace the tubing IMO. I have never had algae in mine, mould yes, Black out micro line if using Fe DTPA ( black insulation tape will do. I would dump all the ferts that have passed your pump if your pump has four rollers, if your pumps has two rollers I would dump the lot good clean, disinfect and freash batch. Store esp Micros in Dark ( best both in dark IMO)
2. Acidifying the micro ferts will help reduce the mould and stabilise the Fe also Ascorbic acid (E300) 1.0gram per Litre Potassium sorbate (E202) 0.5gram per litre

May also be worth checking your Mg levels as Mg deficiency can look like Fe deficiency - easiest way to check it is to toss in teaspoon of epsom salts for every 100litres of Water change weekly for a couple of months. Checking your local water report help

A Full tank shot always helps also
 
Best to alternate two types of iron, DTPA iron and Gluconate iron, to assure bio availability under variable conditions. Gluconate is not pH or light sensitive, but short half life.
 
I'm dosing 1ppm of Mg a week. I did ask the water company about mg and calcium and I don't remember the levels but they were about equal. But we have a salt-free water softener and I don't know how that affects planted tanks. (I researched it and couldn't find anything)

Thank for the info on lines on auto dosers. I will do a good cleaning and replace the solutions. The solutions are in the dark but the lines are not.

I might go back to plantex csm+b because my ph gets low enough for it. I haven't been dosing any other micros besides iron and boron.
 
As @Zeus. says, DTPA chelated iron could be breaking down in the clear tubing before it enters the aquarium. I use this stuff for my micro dosing lines:

Amazon product ASIN B00CAUKI00
I don’t think it will make a difference. You dose DTPA iron during photo period, and the chelation is subject to photo break down anyway. On the other hand, lighting can photo reduce Fe3 to Fe2, making iron more bio available.

 
I don’t think it will make a difference. You dose DTPA iron during photo period, and the chelation is subject to photo break down anyway. On the other hand, lighting can photo reduce Fe3 to Fe2, making iron more bio available.


I don't - I dose micros about 2-3 hours before the photo period to allow some absorption before light on.

It might not be breaking down the DTPA chelate in the tubing, I have no way of testing, but on a 60 litre tank, say you're dosing 10ml of micros, you probably have a large chunk of that sitting in the clear tubing for 24 hours under the entire lighting period. If you've gone to the effort of buying DTPA iron and making up a solution, it just makes sense to me to avoid the possible risk, and preventing unnecessary light exposure.
 
I don't - I dose micros about 2-3 hours before the photo period to allow some absorption before light on.

It might not be breaking down the DTPA chelate in the tubing, I have no way of testing, but on a 60 litre tank, say you're dosing 10ml of micros, you probably have a large chunk of that sitting in the clear tubing for 24 hours under the entire lighting period. If you've gone to the effort of buying DTPA iron and making up a solution, it just makes sense to me to avoid the possible risk, and preventing unnecessary light exposure.
Are you sure plants can uptake nutrients before light on. I was under the assumption that plants only uptake nutrients during active photosynthesis.
 
Are you sure plants can uptake nutrients before light on. I was under the assumption that plants only uptake nutrients during active photosynthesis.

That's what I've seen advised by both @X3NiTH and @dw1305 -

Dosing Micro in the dark gives plants a chance to uptake a bigger dose of Iron before the lights come on which will photodegrade the associated chelate (APFUK Micro is EDTA) dropping out the Iron.

You can feed when you like, nutrient uptake occurs all the time. . . .
 
As others have said blackout the lines and preferentially dose the Micro before lights on, increases the chances of maximal Fe availability for the plants. I was using white opaque RO tubing for my lines then moved to wrapping in tinfoil but eventually swapped to the Fluval black tubing posted above, much better!

A0C46649-6B37-45B3-A5FB-61910A0CF5C1.jpeg


:)
 
Are you sure plants can uptake nutrients before light on. I was under the assumption that plants only uptake nutrients during active photosynthesis.
If you think about it, plants are mostly water right? If your tank water is saturated with nutrients, it’s inevitably going to be absorbed by the plants. That’s how I look at it at least in a less scientific fashion.
 
Hi all,
That's what I've seen advised by both @X3NiTH and @dw1305 -
If your tank water is saturated with nutrients, it’s inevitably going to be absorbed by the plants.
Are you sure plants can uptake nutrients before light on. I was under the assumption that plants only uptake nutrients during active photosynthesis.
I think the difference is between "passive uptake", <"which occurs all the time"> and is driven by the concentration gradient across the plant cell membranes, and <"active uptake">, which is driven by photosynthesis.

cheers Darrel
 
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Is it correct to say that plants uptake CO2 only during photo period to photosynthesize sugar, but uptake nutrients at all time to grow cells by utilizing the sugar energy. In other words, plants do not need nutrients for photosynthesis during photo period as the reaction involves only CO2 and H2O, but need other nutrients for cell growth and respiration that occur at all time
 
So I changed to plantex and changed the dose to the morning when the ph is 6.5 and things have gotten worse.

4 days ago I doubled the dose and still no difference.

I dosed some mg 1 1/2 weeks ago just to make sure it wasn't a mg deficiency and it made no difference.

I find this really interesting, some of my algae is turning white too. My DHG is also starting to turn white and that is new.

I dosed an ei level of dtpa iron today and I will see how that goes.

I have been removing algae and I figured that it would go away once I get the nutrients under control.
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Is it correct that you dont dose any general traces?
Your floaters are quite clearly suffering, and if throwing iron and mg at it doesnt help any I think it could be wise to start looking elsewhere. Many of the trace nutrients can also cause chlorosis when missing, the reason we assume iron is because iron doesnt like to stay in the water and is usually the one thats the problem. I think you should try a good trace fertilizer and see if that helps.
 
I put the floaters in there just to rule out co2 when this all started.

What trace would you recommend? I went back to plantex csm+b about 2 weeks ago.

Does plantex have an expiration date? Mine is about six years old.
 
Hi all,
Assuming the newest leaf on the Spirodela is the green one? Then your plants aren't now iron deficient. They can't move the iron to the older leaves, so they will remain pale.
Does plantex have an expiration date? Mine is about six years old.
No should be fine, as long as there aren't obvious precipitates?

cheers Darrel
 
So I changed to plantex and changed the dose to the morning when the ph is 6.5 and things have gotten worse.

4 days ago I doubled the dose and still no difference.

I dosed some mg 1 1/2 weeks ago just to make sure it wasn't a mg deficiency and it made no difference.

I find this really interesting, some of my algae is turning white too. My DHG is also starting to turn white and that is new.

I dosed an ei level of dtpa iron today and I will see how that goes.

I have been removing algae and I figured that it would go away once I get the nutrients under control.
Hello,
First of all there are no known algae that are affected by Iron. In your original post it seemed that you were having difficulty with the coloration of plants, hence the focus on Iron.

The photos in post 15 reveal this is a typical case of filamentous algae which has nothing to do with iron and I find it shocking that no one has pointed this out already.

Filamentous algae is caused by poor CO2, so you need to fix that first. DTPA or any other alphabet soup Iron will not fix this problem. You may want to reduce your light intensity as this is the primary cause of plants running short on CO2.
I'm confident that it is a nutrient problem and not a CO2 problem
This is exactly why hobbyists suffer CO2 faults, because they are always confident that their CO2 is good even though 95% of tank problems are actually due to poor CO2.

Cheers,
 
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