yellowing leaves, iron deficiency?


Junior Poster
Mar 7, 2009
Hello all, first post here but been reading the forums a few months now..
I'm new to the planted tank world but i've been keeping marine reef aquariums for years.

Anyway im having leaf yellowing problems mostly evident in my banana plant -nymphoides aquatica, water sprite -Ceratopteris, and pennywort -Hydrocotyle leucocephala.

Leaves are very yellowed with the veins a darker green especially in new growth.

the tank is a standard 55gal with some driftwood, lace rock about 3in of substrate consisting of about 2/3 uncoated gravel and the rest a mixture of flourite, oil dry and sand i added after i decided to try my hand at plants.. (the tank was originally a fish only tank).
So my guess with displacement i have around 48 gallons of water and I use that figure to dose.

filtration is a magnum 350 with nothing in it feeding a rex grigg C02 reactor. So basically its for C02 and water movment only.

Nutrient dosing is EI with pressurized C02 and around 3wpg of light (2x 55watt PC bulbs and 2x 28watt T5 NO)

Dosing routine:

every other day:
KN03 -> 2.52g/.45 teaspoons -8.5ppm
KH2PO4 -> .45g/.09 teaspoons -1.73ppm
K2SO4 -> 2.1g/.35 teaspoons - 5.18ppm

every off day:
Plantex CSM+B -> .7g (a little less than 1/8 teaspoon)
and somtimes i add a little leafzone iron though i dont see any results

the tank has a heavy fish load in my opinion at 45 fish 1.5in or smaller and I feed 2x a day. thats why i add a little K2SO4 though i dont understand why other than Tom advises it lol.

Water parameters are:
tap ph - 8.0
tank ph - 6.8
kh- 6-7
gh - 27 (yes 27 ive tested it and retested it several times my tap water is very hard)

I dont test anything else. the tank tells me what it needs.

So with my gh being so high you would assume theres plenty of Ca and Mg. Well i figured maybe its all Ca and I have little Mg in the tap so I've recently been adding a little epsom salt but it doesnt seem to help and is probably just raising my gh..

Any insight or help on what i may be doing wrong or just not doing would be much appreciated. Do i need to add Iron? I see nothing about adding iron in the EI.

btw Ive just recently started using EI and before that I had massive algae problems.. the algae growth has stopped and is gone now for the most part. Thanks Tom!

Tom Barr

Staff member
Jan 23, 2005
Might also be from lack of
Mg, Gh is high, so it might be really high in Ca, and not much Mg.

MgSO4 is what I'd consider, I'd also use Tropica vs Seachem for a iron./trace source.

Plantex is ETDA Fe, so it's fine for low KH water........
That will address Fe and Mg both.

It might be some other thing in the tap water also, get the water report for your area.

Then look at that.

Tom Barr