Chelated iron - yes?, no?, which? - Fertilizing - Aquatic Plant Central

Go Back   Aquatic Plant Central > Special Interest Forums > Fertilizing

Fertilizing Science of Aquatic Fertilizing - Discuss fertilizing techniques and proper aquatic plant nutrition here.

Reply
 
LinkBack Thread Tools Display Modes
Old 01-10-2010, 10:01 AM   #1 (permalink)
Senior Member
 
nfrank's Avatar
 
Join Date: Jan 2005
Location: NC
Posts: 372
iTrader Ratings: 32
iTrader Positive Rating: 100%
nfrank is a regular member
Default Chelated iron - yes?, no?, which?

Yesterday, i mentioned that ETDA iron may not be as stable as HEETA or DTPA. Iron in ferts. Today, i noticed a 2nd post mention EDTA to Bind Heavy Metals. I wondered about the differences of Fe vs other metals, so I thought i would investigate a bit on-line. The internet has become wonderful way to quickly find peer reviewed literature.

One interesting 1998 study, perhaps relevant to aquariums, says:
"FeIIIEDTA has a half life of about 2 hours in sunlit waters. Complexes ofEDTA with other metals do not exchange with iron and are photostable. Therefore, EDTA behaves like 2 different compounds: - FeIIIEDTA undergoes fast photolysis with biodegradation of the metabolites. The other metal-EDTA complexes are persistent in the environment." Biodegradation of the photolysis products of FeIIIEDTA
While, the EDTA detoxification of heavy metals is stable (as mentioned by Diana), the resulting Fe complex is not....although 2 hours is much shorter than i thought. This info may be important for choice and frequency of iron dosing expecially in tanks wo soil. However, sunlight is much wider spectrum than artificial light. I believe the UV may be the culprit (organics are more efficient absorbers of short wavelenths), so 2hr may be an extreme value unless UV filter is used.

Then i got to think about my statement about HEEDTA and DTPA stability. These are the chelators used in Tropica's TMG/TPN which i have used for the past 15 years. One reference i found says they are indeed more stable at high pH, DTPA stability. I have not yet found anything about its photo-sensitivity, although Tropica says it can be dosed weekly and I trust what Claus has been recommending.

What about the stability of other iron additives, like ferrous iron (Fe+2) gluconate (i have never used it, but it seems to be needed daily?) and of other trace element products. CSM Plantex uses EDTA.

Are there other dry trace element mixtures which use better more stable chelators?
nfrank is offline   Reply With Quote

Advertisement [Remove Advertisement]
Old 01-11-2010, 10:07 AM   #2 (permalink)
Senior Member
 
Bert H's Avatar
 
Join Date: Mar 2004
Location: Alachua, Fl
Posts: 5,448
iTrader Ratings: 125
iTrader Positive Rating: 100%
Bert H is a valuable member of the community Bert H is a valuable member of the community Bert H is a valuable member of the community
Default Re: Chelated iron - yes?, no?, which?

EDTA will bind divalent cations, but I don't know how what the affinities for different cations are. While, I can't speak to the stability of Fe chelators, but I use DTPA chelated iron solution. I have hard water, and found adding EDTA-iron always brought on a precipitate. I don't see any precipitation with the DTPA.
Bert H is offline   Reply With Quote
Old 01-11-2010, 10:22 AM   #3 (permalink)
Senior Member
 
nfrank's Avatar
 
Join Date: Jan 2005
Location: NC
Posts: 372
iTrader Ratings: 32
iTrader Positive Rating: 100%
nfrank is a regular member
Default Re: Chelated iron - yes?, no?, which?

what DPTA product do you use, and how often?
nfrank is offline   Reply With Quote
 
Old 01-11-2010, 10:27 AM   #4 (permalink)
wet
Senior Member
 
wet's Avatar
 
Join Date: Nov 2008
Posts: 765
iTrader Ratings: 31
iTrader Positive Rating: 100%
wet is a regular member
Default Re: Chelated iron - yes?, no?, which?

Hi, nfrank. DTPA chelated Fe at 10% concentration is available on most aquarium dry fertilizer sources (GLA/Orlando, Rex, etc). Additionally, I have been told but have not confirmed that Miller's Microplex uses DTPA as its chelating agent.

Using my eyes on and experience with plants as my testing kit -- the same method you discussed in Dummy Question #6 -- even with DTPA I find benefits from dosing daily, with better color (not necessarily shades of red) and leaf size and density forming with regular Fe and micronutrient addition. Though I do agree Tropica's Master Grow is the best micronutrient fertilizer I've ever used, I also preferred to dose it multiple days of the week. (I've never used Plant Nutrition.)

Last two cents is I've put DTPA chelated Fe into Seachem's Excel and dosed it to .2ppm Fe / 5mLs into 10 gallons and was very happy with it as my version of Special Sauce to perk plants up. Some input from our chemists about chelated Fe in a solution with glutaraldehyde is appreciated, though I'm sure fellow nerds are already googling, though most studies are in relation to Fe in blood/hemoglobin.

Quote:
I have not yet found anything about its photo-sensitivity, although Tropica says it can be dosed weekly and I trust what Claus has been recommending.
Only so I understand/for my curiosity: does this mean you find Tropica's relatively low Fe addition in it's recommended dosages adequate for your tanks, or that you trust Christensen's recommendation but also dose more than the recommended doses in your sweet tank?

Thanks for the informative pdf, sorry about the messy post. Stop distracting me from work, APC, dammit.
wet is offline   Reply With Quote
Old 01-11-2010, 10:37 AM   #5 (permalink)
wet
Senior Member
 
wet's Avatar
 
Join Date: Nov 2008
Posts: 765
iTrader Ratings: 31
iTrader Positive Rating: 100%
wet is a regular member
Default Re: Chelated iron - yes?, no?, which?

Quote:
Originally Posted by Bert H
I have hard water, and found adding EDTA-iron always brought on a precipitate. I don't see any precipitation with the DTPA.
Quote:
Originally Posted by nfrank
what DPTA product do you use, and how often?
Not exactly the same, but you guys might like these pics from an old demonstration I did on some other thread, especially in regards to time percipitate forms. The time indicated is time between DTPA chelated Fe input (what would be 0.5ppm Fe into my tank's volume) and KH2PO4 input (2ppm, same). The pic was taken approximately 5 minutes after adding KH2PO4 into each container. IIRC I bought this DTPA Fe from Rex.





wet is offline   Reply With Quote
Old 01-11-2010, 11:35 AM   #6 (permalink)
Senior Member
 
nfrank's Avatar
 
Join Date: Jan 2005
Location: NC
Posts: 372
iTrader Ratings: 32
iTrader Positive Rating: 100%
nfrank is a regular member
Default Re: Chelated iron - yes?, no?, which?

[QUOTE=wet;516691]Only so I understand/for my curiosity: does this mean you find Tropica's relatively low Fe addition in it's recommended dosages adequate for your tanks, or that you trust Christensen's recommendation but also dose more than the recommended doses in your sweet tank?
QUOTE]

With my soft tap water (KH<2), and moderate additions of minerals (1t CaSO4, plaster + 1t Epson salt to 60gallons of replacement water), i have been dosing 45-50 ml TPN weekly. In older tanks, i recall that i dosed 20ml per 70gal. I believe both are less than Tropica's recommended amounts on the label. My tap water does provide some iron, and the AS might provide some. My previous tanks also had some iron in the substrate.

Once i stop playing with macros, i would be willing to experiment with adding extra Fe. I do prefer a product that does not have to be added daily.

The Iron - PO4 precipates are interesting. If i remember, i will try that with TMG. Precipates are not necessarily all bad, at least for the plants i like to keep The Fe can resolublize once it settles into anaerobic zones of the substrate. As we know, ferns however, depend on the water column. So, i have to beleive that i am maintaining high enough levels to keep them happy. I also have a nice crop of Riccia attached to the intake of my overflow.
nfrank is offline   Reply With Quote
Old 01-12-2010, 04:11 AM   #7 (permalink)
Senior Member
 
nfrank's Avatar
 
Join Date: Jan 2005
Location: NC
Posts: 372
iTrader Ratings: 32
iTrader Positive Rating: 100%
nfrank is a regular member
Default Re: Chelated iron - yes?, no?, which?

Quote:
Originally Posted by nfrank View Post
what DPTA product do you use, and how often?
I am still very interested to learn how often folks use DPTA chelated Fe.... and if anyone has done Fe tests to see how stable are the concentrations over several days or longer.

Apparently, this conversation occurred years ago on APC. For example, I found this. See HeyPK's Comments. I checked the product he mentioned and found it is still available. Iron DPTA

I looked at my Fert Box, and found i still have over a pound of 10% FeDPTA.

So how do folks use it, how much, how often? I am hoping it doesnt have to be used daily, and someone has data to demonstrate this
To dispense traces dry, this would be helpful: Pinch spoons. Similar dispensors come with aquarium test kits. I need to hunt for mine.
nfrank is offline   Reply With Quote
Old 01-12-2010, 11:00 AM   #8 (permalink)
Senior Member
 
Bert H's Avatar
 
Join Date: Mar 2004
Location: Alachua, Fl
Posts: 5,448
iTrader Ratings: 125
iTrader Positive Rating: 100%
Bert H is a valuable member of the community Bert H is a valuable member of the community Bert H is a valuable member of the community
Default Re: Chelated iron - yes?, no?, which?

Quote:
Originally Posted by nfrank View Post
what DPTA product do you use, and how often?
I bought a fairly large amount of it from Greg back when he had his on-line business. I use 2 ml of Flourish, and 1ml of the iron chelate on my moderately lit 50's 3-4x/wk. I've never known how folks can add the humongous amounts of iron they do and not have problems. I tried increasing the amounts for a while, but it seemed to correlate to an increase in gda. I can't see where my plants need any more than that. Maybe if I had more lighting, it might be needed.

I've never bothered to try to figure out how long it remains available.
Bert H is offline   Reply With Quote
Old 01-12-2010, 12:38 PM   #9 (permalink)
Senior Member
 
nfrank's Avatar
 
Join Date: Jan 2005
Location: NC
Posts: 372
iTrader Ratings: 32
iTrader Positive Rating: 100%
nfrank is a regular member
Default Re: Chelated iron - yes?, no?, which?

Quote:
Originally Posted by Bert H View Post
I use 2 ml of Flourish, and 1ml of the iron chelate on my moderately lit 50's 3-4x/wk.
What is 1ml of the chelate mean? Isnt it a powder?
nfrank is offline   Reply With Quote
Old 01-12-2010, 04:26 PM   #10 (permalink)
Senior Member
 
Bert H's Avatar
 
Join Date: Mar 2004
Location: Alachua, Fl
Posts: 5,448
iTrader Ratings: 125
iTrader Positive Rating: 100%
Bert H is a valuable member of the community Bert H is a valuable member of the community Bert H is a valuable member of the community
Default Re: Chelated iron - yes?, no?, which?

Quote:
Originally Posted by nfrank View Post
What is 1ml of the chelate mean? Isnt it a powder?
Sorry, I didn't clearly state it. Yes, it is a powder (Fe 10% in DPTA). I make a 10% solution (10g/100ml water) and dose from there. It ends up being the same as Flourish Fe solution, strengthwise.
Bert H is offline   Reply With Quote
Reply


Aquatic Plant Central > Special Interest Forums > Fertilizing > Chelated iron - yes?, no?, which?

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -8. The time now is 02:52 PM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.

Search Engine Friendly URLs by vBSEO 3.6.1