pps pro and high nitrates in tap water

[dw1305]

Hi all,

I'm using Seachem Flourish Iron because it is Fe+2 rather than Fe+3 and I thought it would be easier for the plants to take up Fe+2 iron form.

It doesn't really make any difference whether the iron is ferrous (Fe++) or ferric (Fe+++). Technically the ferrous iron ion (Fe++) is more easily taken up by plants than the ferric (Fe+++) ion. In practice as soon as you are above pH7, and in an oxidising environment, then any Fe++ rapidly becomes Fe+++ and then an insoluble Iron III oxide or hydroxide. Iron II compounds are green in colour and iron III compounds rust red.

A chelator works by binding the iron ion in a stable compound, it would remain unavailable (Fe+++ is the most tightly bound ion) but the EDTA etc is photo-degraded by sun-light and the iron ion becomes plant available briefly before forming an insoluble compound. Some chelators are better than others at high pH, and I would suggest <"FeDTPA"> might be a better option for you. <"FeEDTA"> would be cheaper, and I use it if I need a chelator for hydroponics etc even at higher pH levels.

Since adding iron Fe two weeks ago, the leaves are now a richer green and the ruben ludwiga is retaining more red colours.

If the new leaves are pale, and you have hard water, iron deficiency is an option. Iron is non-mobile in the plant, and nearly all the other nutrient deficiencies (N, K, (P), Mg) that cause <"chlorosis"> are mobile elements so effect the older leaves first.

cheers Darrel