Re: Stock Solutions

[Paul Sears <psears at nrn1_NRCan.gc.ca>]

> From: Brown_D at pcfnotes1_wustl.edu
> Subject: Stock solutions
> 
> I actually haven't made any stock solutions for my tanks yet.....but I
> would start with dry chemicals and an accurate scale and make a large
> volume of concentrated solution, say 500 cc, so that I could then do a 100x
> dilution with an accurate teaspoon (5cc) or better yet, a pediatric dosing
> syringe,into another 500cc, and so forth.  That's a lot more accurate than
> trying to measure 0.01cc with most commonly available household equipment.

	The chemist in me says "That's the right way to do it!", but the
gardener actually grabs the bottle of reagent off the shelf and "measures"
some out with the end of a spatula.  I actually measure iron and nitrate
concentrations in the tank, to help decide _what_ to add, but I never
worry too much about how much.  Observation of what is going on in the
tank also plays a big part in the decision of what to add.  I should
add that I have weighed enough chemical samples accurately that I have 
a fair idea how much is on the end of the spatula!

> Diane Brown, MD, PhD

Paul Sears, MA, PhD (chemistry)

-- 
Ottawa, Canada