# Re: Can someone check my math?

```Jerry Leong wrote:
> Aaron Ivers  wrote:
> Subject: Can someone check my math?

> Is it acceptable to assume that 1 mL of this stuff then
> represents (1000 mg x 97% x 30%) or 291 mg of PO4?
> > Also sounds good.

>>Concentrated Phosphoric Acid is much denser than water
(approx. 1.8(?) for a 97% concentration) - a 30% sol. is approx.
1.2.  This means that unless your calculations include the
differences due to the specific gravity and if you are using a volume
measurement (ml), you'll be adding approximately 20% more
phosphate than you think you're adding.<<

Since you're using volumes, density _doesn't_ matter. 1 ml still
contains a solution with a concentration of 291,000 mg per liter
PO4. 1 ml is 1/1000 of a liter, or:

1 ml x 291,000 ug/ml = 291,000 ug = 291 mg.

If you didn't have a way of measuring volume, you could
theoretically weigh out the solution to get 1 ml total volume, which
would be ~1.2 g, based on a density of 1.2 g/cc.

1.2 g / (1.2 g/cc) = 1 cc = 1ml.

Jamie    <"\\\>< Aquatic plants, water chemistry, and cichlids
Greenwood, SC     http://www.ais-gwd.com/~jjirons

```