Backyard Aquaponics
A place to discuss aquaponics

Mattyoga:

here a shot of how well the Bok Choy picked up

would seem to provide a degree of proof...

wow BokChoyk and Cheese! I've ordered DTPA so will see if the deficiency I've got changes when I add it to the system and will update the post.

How much did it end up costing all up or did they send it C.O.D

Not found out yet - no charge on my card, no product arrived - will chase them up in a few days...

Added some eddha to my tanks and the water is now red. Fish seem happy

Mine's so red that I can't even see my fish... I am going to start doing partial water changes to get rid of the red as I am now using DTPA and the red from the EDDHA hasn't cleared at all over almost 2 months!

$17.10 postage + $24 for 1kg of DTPA Iron $41 for a kilo is not too bad considering yates edta is $23 for 500g

Can I ask where you are getting it from. Not happy with the red water and had to do a third water change to be able to see the little silvers again.

I ordered mine from here:
http://www.duralite.com.au/iron-dtpa-dissolvine/

I might order some myself, as DTPA Iron chelate isn't available locally.

Just make sure you don't pour too much in though, ~600g into my system = 100ppm will kill half the trout.
>> Acute toxicity Oncorhynchus mykiss, freshwater, static: 96h-LC50 > 100 mg/l (OECD203)

Good point - also emphasizes that iron testing is needed if supplementing with iron. This link gives the manufacturers dosing instructions:

http://www.mgshort.com/images/dissolvin ... _sheet.pdf

Which if I'm reading it write states 8g/1000L of product (i.e. 11% DTPA Fe Chelate) for soil less media (table A)

It's very hard to get the right dose on this one, Dr. Nate Storey says

"Fish will be fine up to 2mg/l. Don't try to go above that number" (quote)

2mg/l x 1000 = 2grams

8grams stated in PDF sheet is 4 times Dr. Nate Storey's dose and he states not too go above 2mg/l.

The fine print reads: "For the dose rate of a 1m2 tank. 100 times concentrated: Multiply the amount of grams mentioned with 100"

Who has the correct dosage on this stuff? I'm adding 9.2 grams DTPA per week to 1400 litres based on my calculations below and at that dose it doesn't read with the Iron Test Kit.

2mg/l every 3 weeks (2 milligrams per litre)
2mg/l = 7.58 mg/gal
11% DTPA = 0.11
= 68.9090909 milligrams per gallon
1400 litre System = 369.8409 us gallons
68.9 x 369.8 = 25479.22 milligrams
25479.22mg = 25.47922 grams
25.5 grams every 3 weeks = 8.5 grams per week


Someone must have the correct dose per litre.

Going by the splotchy leaves probably manganese



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

Yeah. They're still splotchy and pale. Not added iron yet as its not arrived. Will try some and see if that makes a difference before looking at manganese. Would seasol provide enough manganese? I've not been dosing much with it lately as the system is a year old now.