02-03-2013, 01:25 PM
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First point, is that iron is not usually the "missing" nutrient. Swords are heavy feeders, and that means all 17 nutrients must be available balanced with light intensity obviously. Iron is a micro-nutrient; and it is also a heavy metal and all heavy metals can kill all forms of life (fish, plant, bacteria) at high levels. Plus, an excess of some nutrients can cause the plant to develop a deficiency of some other nutrients, and excess dosing of any nutrient is inadvisable.
Back in the 1990's I experimented in one tank with laterite, an iron-rich clay that goes as a layer under the overlying gravel/sand. The same sword species in this tank and in my two other tanks grew no better for this.
More recently, for almost two years i had my 70g set up with Flourite substrate. This was a real disappointment, and the swords in this tank have been struggling throughout. I've no experience with FlorMax, but personally I would not waste the money. This past week I torn this tank down and it is now reset with plain play sand.
Swords will grow fine with good liquid fertilizer, provided it is complete and balanced. Seachem's Flourish Comprehensive Supplement or Brightwell Aquatics' FlorinMulti both provide this. I have grown several sword species in tanks with plan gravel or sand substrates using just the liquid. However, the larger swords [meaning, other than the pygmy chain and chain species, do fare much better with substrate fertilization but it has to be complete. I have incredible growth from my larger swords using Flourish Tabs once every 3 months. Don't know why you would object to this, but if you want good plant growth bite the bullet.