Iron test results difficult for me to read

[Seabiscuit]

I bought a Seachem Iron Test Kit and have run 5 test so far to get my aquarium's iron level. I have several macroalgae and some people who grow macroalgae suggest dosing iron because their plants do better with it. I also have a few fish in the tank, but no corals. I bought a bottle of Brightwell Aquatics Ferrion and have not put any of it in my tank yet because I don't know if the tank is low on iron or not. I get the same results from the test every time. There are dark purple "precipitate" or chunks that form a few seconds after mixing the reagent and sample in the cell and they always form at the surface of the cell reservoir. I contacted Seachem and they wanted some photos to determine what was going on, but they did not explain the precipitate I was experiencing and said that I should be confident that my test is working properly. My thoughts are that the precipitate is holding onto some of the coloring pigments that should be part of the uniform color in my test results.
My questions are: Are these normal results? Is there a better multi-test iron kit that somebody out there is using and happy with?

 

[Randy Holmes-Farley Verified Community Expert]

I'm not familiar with the details of their kit, but no iron test kit can detect down to natural levels. I'd suggest not testing for iron. Even ICP cannot test that low.

One does not need to test to dose iron usefully.

i discuss iron more here:

Chemistry And The Aquarium: Iron In A Reef Tank

Randy discusses iron and its usage in our aquariums.

reefs.com

and

Chemistry And The Aquarium: Iron: A Look At Organisms Other Than Macroalgae

I do believe, however, that the benefits outweigh the risks when one is growing macroalgae. To date there have been no claims of a demonstrated problem in a reef tank from reasonable iron additions.

reefs.com

 

[Seabiscuit]

I'm not familiar with the details of their kit, but no iron test kit can detect down to natural levels. I'd suggest not testing for iron. Even ICP cannot test that low.

One does not need to test to dose iron usefully.

i discuss iron more here:

Chemistry And The Aquarium: Iron In A Reef Tank

Randy discusses iron and its usage in our aquariums.

reefs.com

and

Chemistry And The Aquarium: Iron: A Look At Organisms Other Than Macroalgae

I do believe, however, that the benefits outweigh the risks when one is growing macroalgae. To date there have been no claims of a demonstrated problem in a reef tank from reasonable iron additions.

reefs.com

Thank you so much. I will read your articles today.