Hard tapwater and iron deficiency

Hi,

My first post here

I think I experience iron deficiency symptoms in my low-tech tank (greenish nerves enclosing new pale-yellow leaf tissue), even though I dose 5 ml TMG twice a week plus 5 ml Flourish once a week, and still have the symptoms. My tank is just 27 litres (about 7 US gallons). The deficiency is very clear in h. polysperma. Even cabomba aquatica is very very bright-green. I can add that I dose a lot of KNO3 and KH2PO4.

Here in Uppsala, Sweden we have very hard water, around dH 16, if that is relevant.

/Patrik.

 

Re: Hard tapwater and iron deficiency

Allrigt, here it is in short:

Tank: 27 liter
Light: 11 w PC
Dosing: KNO3 up to about 30 ppm, KH2PO4 around 3 ppm
non CO2, just Seachem Excel, about 5 ml every day
I try not to do waterchanges at all, I try to follow T. Barrs "non-CO2 method"

/Patrik.

 

Re: Hard tapwater and iron deficiency

Allright, I try with a waterchange. I was also thinking that it could be my high pH (around 7,5) that caused the iron supplement to become unavailable/less available to the plants. As I use Seachem Flourish that has iron in Fe2+ state (which should be very easy for the plants to take up) I tried googling on iron ph, and found this:

"IRON OXIDATION

The time required for uncomplexed ferrous iron to undergo oxidation to the ferric state is dependent on many factors, the dominant being: pH; temperature; dissolved oxygen level; and the presence of other soluble ions. The lower the pH and temperature the longer the time required for completion of the oxidation reaction. Increasing dissolved oxygen decreases the time required for oxidation. For example:

At pH 7.0, 90% Fe+2 oxidation requires 1 hour at 21o C and
10 hours at 5o C. At 21o C
At pH 8.0, 90% Fe+2 oxidation occurs in 30 seconds,
at pH 6.0 it requires 100 hours.
The critical dissolved oxygen concentration is 2 mg/L. Below that ferrous iron oxidation occurs slowly."

Source: http://2the4.net/iron.htm

Could my iron deficiency be linked to high pH?

 

Re: Hard tapwater and iron deficiency

Aha, so Tom, as long as I use TMG then I can forget about such things as pH and water hardness? Just dose TMG twice a week and be done with it?

/Patrik.

 

Re: Hard tapwater and iron deficiency

Thank You, Tom!

/Patrik.