How fast is Iron absorbed?

[hypersushi]

I don't have any Iron test kits so I can't measure this. My question is, if I dose liquid iron ferts for my plants in the morning, would it be okay to do a WC in the afternoon? This is assuming I have healthy and semi dense planted tank with mainly stem plants and maybe two to three types of red plants. Assume that I also dose according to directions and I am hovering around the 2.7 WPG region. Can someone advice me (if you have done tests before). I don't want to waste the liquid iron for nothing....

[richietay]

why aren't you do dosage after water change?

[dc88]

Hi

I am not chemical trained, only read a little background of the way the chelated Fe works (one reference is the book Ecology of the Planted Aquarium by Diana Walstad). Basically the Iron fertilizer is Fe binding to some chemical complex (called chelator, e.g. FeEDTA-) which the Fe in it does not available to plant all at once. Under the reaction by the light (certain wave length of the light) FeEDTA will breakdown and release the Fe ions that plant can absorb.
The Fe test kit basically measured how much of the free Fe available in the water at any one time, release from the "FeEDTA reservoir" that you dosed in the tank.

If you make a water change after dosing the FeEDTA, you basically wasted it thats all.

Rgds
DC

[hypersushi]

why aren't you do dosage after water change?

Forgive me if I'm wrong, but should we fertilize iron everyday? I normally put dose iron the day before I do a WC. However, that day, I forgot to dose the day before: hence the question...

[valice]

Err... Still don't understand why you don't dose after WC instead of before... Makes more sense regarding the part of not wasting right?

You don't need to dose iron everyday as it is a micro nutrient, so it is not the main building blocks of the plants... Every other day will suffice... That is assuming you are dosing N, P and K and providing good CO2 with your lights...