Backyard Aquaponics
A place to discuss aquaponics

Here are the choices:

Iron DTPA 11% for alkaline use
Iron EDTA 13% for acidic use
Iron EDDHA 6% for alkaline use

The EDTA would be my choice I think because we generally try and keep things a tad acid rather than alkaline.

Fe-EDTA is bad. and unstable. EDTA would much rather bind with calcium. Plus EDTA breaks down into bad phytotoxic things. Fe-DTPA is great as long as you control the amount of sunlight hitting the water.

And you forgot Fe-HBED. ;-} It's a fruit-punch variant in that it will color your water red, but the red is much less intense than Fe-EDDHA. And it's the most UV-stable chelate.....

I know this is a real rookie question, but acidic is low oh and alkaline high? My brain has never been able to keep the whole high ph is x and low oh is x. I think it's because my brain decided more acidic should be higher ph for some reason, which I believe is incorrect.

Now that I've rambled, I'm interested in the above question, especially in regard to systems with high ph(or a wide ph range anyways), as that is how my system currently sits.

They didn't have that one in their list I'll ask.

Yep as you said more pH lower number. Higher pH more alkaline with 7 being the neutral point.

Cool, I got a quote for EDDHA awhile back because my reading (and I think it was mainly based on Bright Agro info) suggested it. Will follow this post as I want some iron at some point... Thanks (and apologies I've asked more questions rather then contributing ahaha)

Bcasey the problem with EDDHA is the blood red colour it dies the water,its a very good product but not if you ever want to see your fish again....

There is one other choice Stuart. Let's not forget that regular iron like what you find in Maxicrop plus Iron works depending on the pH. Just because it's regular iron doesn't mean you aren't supplementing what's in the system.

Yes, well...what is regular iron?

The supplier I was talking to don't stock EDDHA anymore because of the problems they were having with it. They had never heard of HBED.

I've got a couple of pound of research-grade Fe-HBED. Dickens to find. Works like a treat even if you have a UV sterilizer running. So effective at chelating the iron that some algae cannot extract the Iron. It's sitting on my shelf since i'm running Fe-DTPA for the winter so I can see the fish.

By normal I mean bio-available Ferrous iron although iron really is in a lot of forms. At pH's over 7 it's less likely to be in this soluble form. There's no guarantee that you'll find it in a bioavailable form at lower pH's either. There are other possible supplements for Iron as well.

It's also possible to have plenty of Iron in the system but not have enough available when your pH is in the right range. I was reading this article - http://www.skepticalaquarist.com/ferrous-ferric and toward the end he suggests adding organic chelating agents instead of Iron (Scroll to the last paragraph unless you want to read it all). Basically you'd be chelating the Iron that's already present in your system and making some of it available that isn't. Think of all the Iron you've added, did it all get used by the plants? Probably not.

I thought the whole point of adding iron in these forms was because it was available. Otherwise we would just throw a horse shoe or two in.

So how many horseshoes per 1000L should we be adding?

Thats an interesting article thanks for that scotty.

Anyone tried keeping Seahorses in AP,you could there shoes on them.....