[hermione2884]

I'm investigating the effects of concentration of aquasol fertilizer on the length of seedlings.

So the aquasol that we were provided with was already diluted (i think 80% concentrated with aquasol. We further diluted this solution to the concentrations that we wanted which was 0% 25%, 50%, 75% of aquasol.

I noticed that other people had written their concentrations as 0.5%, 1%, 1.5% and 2% but I'm not sure how they got these values?
 
Hope that made sense!

[Arkcon]

Well, this is one of the sorts of questions that rapidly go nowhere, but, I'll bite ...

Either you did what you said you did, and you're correct.  And they did what they said they did, and are also.  Or maybe neither.

Maybe you're correct about the initial dilution, or you're not.  And maybe you've compensated for that, or didn't.  Which would make you wronger, or simply wrong, or correct, depending ...

Why not write out, for yourself and us, what you did, to get the concentrations you wanted.