[dski13]

Hi I am new to all of this and have some questions. When you are all talking about dry ferts are they pure chemical or do they have filler? If I have a bottle of lab grad KN03 would that be the same as the dry ferts you are talking about? Also does anyone have a dosing regime in molar concentrations? Calculating ppm drives me nuts. I am particularly interested in a trace mix that has molar concentrations.

Thanks.

 

[Hoppy]

The dry chemicals we use are not lab grade chemicals, but agricultural grade. They are intended to be pure chemicals, with no intentional additives. I don't know why we use ppm concentrations vs. molar concentrations, but they aren't hard to do, until you add the complexity of expressing them in terms of a specific compound - like "carbonates as calcium carbonate".

 

[dski13]

Thanks for your info it clarifies a few things.

 

[Darkblade48]

As Hoppy mentioned, we use agricultural grade, but if you have access to lab grade, then all the better.

I use lab grade chemicals to make my 4 dkH reference solutions for my drop checkers. :smile:

As for ppm versus molar concentrations, it might be due to a combination of convention (whoever started it) and ease of expression; now, we can say x ppm of nitrates are required as opposed to y M(olar), etc.

The chemist in me understands your confusion though

 

[Bluek24a4]

Don't we also use PPM because that's what our test kits read in?

 

[Diana]

Or do our test kits read in PPM because that is what we use?

Which came first!