I have made my first batch of PPMD using the recipe at

http://www.nfis.com/~hartland/aqua/pmdd.htm

I used Grant's Stump Remover for potassium nitrate, Epson salt for magnesium
sulfate, and sulfate of potash for potassium sulfate. I did not use the
Chelated Trace Element Mix. However I do use Flourish Iron and Trace.

My Nitrates are at zero both in the tank and out of the tap, measured with
an aquarium pharmaceuticals nitrate test kit. The kit reads from 0 to 160
ppm with the lowest colors being 0, 5, and 10ppm. Not the best resolution
for low levels but its what I have.

Using the calculator at

http://www.csd.net/~cgadd/aqua/art_p...osage_calc.htm

I determined it would take 8.5 ml of PMDD to raise the nitrate level of tap
water to 5ppm. I added this does to a 5 gals of aging tap water before bed
and tested in the morning. The nitrates were still at 0ppm.

Is something wrong with my PMDD, test kit, or my math?

I do not want to start adding nitrates to the tank in any large amouts until
I know I can measure and control them.

Thanks
Scott