Iron test kits
I was asked for the recipe for Iron test kits the other day and here is
A 20% Potassium thiocyanatesolution with 1M HCl or HNO3.
The post the other day was wrong where I said that it was Sulphuric acid,
it should not be used because it can form complexes with the iron and
reduce the colour development. Phosphate is a serious inhibitor of colour
development and I personally beleive that colour development under these
conditions may take several hours (not the three minutes that sera test
All of the tests that are used in the aquarium test kits can be found in
the book "Vogel's text book of quantitative inorganic analysis". There
are three "Vogel's" make sure that you get the quantitative one and not
the qualitative or organic ones.