hi I was thinking of getting either a Flourite or Onyx sand as a sole substrate for my 4 ft tank. From the Seachem website the impression that I got was that they are both essentially the same apart from colour and buffering capacity. However on paper it seems different. This is from their website: (http://seachem.com/products/product_pages/Flourite.html
Concentration of nutrients in Onyx Sand™
Concentration of nutrients in Flourite™
Units=mg/kg, source: Plasma Emission Spectrometer, EPA Method 3050, Univ. of Georgia Chemical Analysis Lab
Particularly the iron content in Flourite is alot higher than Onyx (on paper). Does anyone know the correct way to interpret this data? I am not a scientist and can't draw any conclusions and any help would be greatly appreciated. Thanks alot guys.