MicB said:

You still have trouble somewhere.

Can you state exactly what the problem is. Give your statement/calculation and the correct? calculation so we can compare the two and see the problem.

Thanks

Ok...

The Flourish Phosphorus bottle has the following formula: 0.8*v*p = m, where...

v = the volume of the tank in US gallons

p = the desired phosphate increase (ppm)

m = the amount of Flourish Phosphorus to use (mL)

Using the fertilator's calculated Phosphate increase (1.59 ppm) in the 15 gallon tank:

m = 0.8*15*1.59 = 19.08 mL (clearly different than the 2 mL I put into the Fertilator to get the 1.59 ppm result) So this is the error.

What should 2mL yield? 0.8*v*p = m -> p = m / (0.8*v)

So... p = 2 / (0.8*15) = 1/6 = .166666... ppm. This is the correct answer, which the fertilator does not produce (it produces the aforementioned 1.59 ppm increase).

^iMp^