Backyard Aquaponics
A place to discuss aquaponics

Seasol contains manganese but at 2mg/litre probably better as a maintenance dosage than to overcome a deficiency if that's what it is

Looking at your previous photo's I think you have pretty much nailed it.
Why add anything/anymore if it's not needed [/quote]


Matthew:

I got my dose right by just increasing each week until the plants picked up and not dosing every 3 weeks as suggested, the thing that I can't work out is why it doesn't read with the Iron test kit.

The EDDHA did but the DTPA iron does not show up at all.

Have you tried dosing and testing a control sample outside of your system ?

Could it be that your system is using it up , or are you testing straight away and perhaps not mixed through the system thoroughly ?



Anyways your plants look heaps better....

Cheers

I've tried it dosed right up in a bucket and it still wont read, the EDDHA is OK but the DTPA doesn't show up at anywhere near the correct dose, maybe if I took it well over the limit it may read.

Matthew I'll give it a try on Saturday and let you know what happens.

I think that I have an iron deficiency and have not been able to source Chelated iron or seasol locally , I have started to add murungai leaves to my fishes diet since I have read it is a good source of iron, not sure if it will work or not but worth a try. Has anyone tried this before?

MarkZ:


Moringa oleifera (Murungai in Philippines) seeds are used for water purification and also been used as fish feed, there's quite a lot of information on the net. Some tests have been done on steaming the leaves with good results.

I don't know how much iron you would get from the fish solids but everything helps.

http://aquafishcrsp.oregonstate.edu/Div ... nzania.php

great ! thank you for the link

Which test kit are you using?



This link suggest that you have to wait much longer to measure chelated iron.

http://www.vitamingrocer.com.au/MultiTe ... ent=308065

and from:
http://www.seachem.com/support/forums/s ... php?t=3648
"To address your question about iron test kits. I would not go to the length of saying that they are all inaccurate and not to bother with them. As a matter of fact, they can be very accurate as long as they are compatible with the the type of iron you are testing for. There are indeed different types of iron that are supplemented to an aquarium. The 2 main types of iron used in the aquarium are chelated iron and non-chelated (free) iron. Chelated iron is in the ferric state (Fe3+) and must be reduced to the ferrous state (Fe2+), which is the preferred state for plants. In doing this reduction, the plants have to expend a great deal of energy. Our Flourish Iron is already in the reduced Fe2+ state and allows the plant to readily take in the iron almost immediately without using any energy.

So, of course, with the different types of iron, there is a need for different test kits. If you are using a chelated iron supplement then you will want to make sure that your test kit measures chelated iron. If you are using say our Flourish Iron, which is not chelated, then you will want a test kit that measures non-chelated or free iron for an accurate reading. Whether one is preferable over the other, I guess that will depend on what iron supplement you are using. Our MultiTest: Iron kit measures both chelated and non-chelated iron, so there is no need to worry about inaccurate results. "

Maybe DTPA holds onto its iron better than EDHHA and so takes longer to show up in the test?

Matt:

Thanks for the links, they throw a bit more light on the subject. Matt it's very hard to find the right information, it's like pulling teeth.

They say:

"For chelated iron, allow color to develop for 30 to 45 minutes or until the color no longer darkens."


I'll give that a try in the morning, that could be the reason I'm not getting a reading.

Some of my chard was starting to look paler than it used to, and the recently planted corn had definitely become a lighter shade of green, and with DTPA being unavailable locally, and quite expensive to buy and freight half way across the country, I used some Growth Garden Care Blood and Bone instead. I added 300g on 20/9, and has darkened the plants up considerably.
The analysis says Nitrogen 9.9%, Phosphorus 3.7% and Potassium 7.4%, and Iron 0.11%, as well as various other elements.

So.. does that suggest you might actually be a bit low on Nitrogen... rather than Iron?

I dont think so- the tomatoes certainly didn't look pale, nor did spring onions, celery, cabbage, broccoli, strawberries or anything else I have in ATM.

Did you notice any change in the ammonia/nitrite levels or did your system handle it with no fluctuation?

I haven't tested A,N,N for a few weeks, so dont know for sure, but I expect it handled it without much fluctuation. The nitrifying bacteria are hard at work producing H+ ions, I'm continually having to add alkali to prevent pH going too low, and didn't notice any changes with that.

Matt:

I tested and waited over an hour and still no reading.



Matthew:

I tested outside the system by putting 1/2 teaspoon of DTPA in a glass of water to see if it would read at that very high level and this is the result. Matt I also left that sample for an hour and there was no change in colour.

It's nowhere near the same colour as EDDHA Iron so I think the test kit I have must be for testing EDDA iron only and there must be another test kit for DTPA Iron.

So guys I'll search further and see if I can find a test kit that suits DTPA Iron.