Calculating Fe dose

[GaspingGurami]

Can anyone be kind to help me with calculation of Fe dosing for Seachem's Flourish Iron?

On the instructions it says "Use 0.5-1ml for each 40L as required to maintain about 0.10mg/L" It also says "Flourish Iron (TM) is a highly concentrated (10,000 mg/L) ferrous iron (Fe+2) gluconate supplement."

If I dose this iron to my 20L water volume, does it mean that 0.5 ml will give 0.1ppm of iron to the water?

I'm in need of help here as I'm unable to do sums like this.

Thanks

[Plantbrain]

Add 1.5 mls 3x a week, this will supply your plants with all the iron they will need even add very high light levels.

Much easier than testing and more effective.
I do not know of any decent iron testing method for a hobbyist.

This amount assumed you have CO2, and good macro dosing and high light etc. You might be fine with 1mls 3x a week if you have lower light.

Regards,
Tom Barr