how do i determine concentrations of premixed solutions?

[Nillo]

I just need some math for this one. If I have a liquid hydroponic trace solution that I want to use up that has a Fe concentration of .2% how do I determine how much to add to get a concentration of .4ppm iron in a 250L tank.

Thanks

[Tom Barr]

100% is well, 100% of the solution, so 1,000,000 ppm, or 1 kg /liter.

What is 0.2% of of 1,000,000?

2000ppm or 2000mg/l

250 liters is 250,000 mls.

I think you should be able to work the rest.

Regards,
Tom Barr

[Nillo]

great thanks for the confirmation.

[Tug]

It's well known how bad I am at this sort of thing (bad, really bad), but you will need 50ml hydroponic trace solution to add .4ppm Fe to a water column that size.
=.4/2*250
= 50