G'day, been down in Mickey land getting hot. ? has my email gone crazy or
has there not been any email to the RML for the last week until 6/12? I
guess I'm the closest thing next to a chemist (a biochemist) on the list so
I thought I check the numbers for you. Shame on you :-) Bruce by being off
by 1000! We used to have a fellow in the lab that would say
"milligrams/micrograms what's the difference"? His samples were always
funky. 30 g is correct for 100 liters, actually 30.77 :-) Adrian did a
real good job explaining everything except he missed a few spots. For
anyone hoping to figure it out for your next calculation (whatever it may
be) I'll just mark the changes with a **
>To calculate the dose rate of a chemical required in a given volume of
water
>the formula is:
>Dose rate = required ppm x volume of water to be treated ÷ (% of active
>ingredient x 1,000,000)
>
>Example:
>To calculate the dose rate of 200 ppm of a chemical with an active
>ingredient of 650 grams/Kg in 100 litres of water = 200 ppm x 100 litres ÷
>(65% x 1,000,000)
>
>Active ingredient of chemical is 650 grams/litre = 0.650 grams/milliliter
>You need 200 parts per million (ppm) which translates to 200 milligrams per
>litre (mg/L)
>(1000 grams = 1 litre, 1000 milligrams = 1 gram, 1 million milligrams = 1
>litre or 1 mg/L = 1 ppm)
**100 litres at 200 mg/litre = 20000 mg or 200 grams ** equals 20 grams (see
above mg to g, remove 3 zeros)
20 g divided by .65 = 30.77 grams. For my money I like to figure the total
amount of "stuff" needed first, like 200 mg/liter multiplied by total
liters. Convert into something somewhat understandable (grams) by losing 3
zeros. Then divide that number by the activity. That way I know that I
need a total of 20 grams of active ingredient to get the job done in this
case. If I mess up and end up multiplying by .65 I'll catch it because my
final number will be less than the "active" ingredient needed. Although my
professional life is consumed with micrograms (10 to the -6), nanograms and
picograms(10 to the -12) I still operate in gallons when it comes to
aquariums :-) It would be so much easier to just give up and convert to
liters!
BTW if you dig roller coasters The Hulk at Islands of Adventure is a pretty
good ride.
gary lange
>200 grams needed divided by 0.650 grams/mil of chemical = 300 milligrams
per
>100 litres of water
>
>I HOPE that's right - anyone else done the calculations????
>
>Adrian.
>
>
> Adrian R. Tappin
> Brisbane, Australia.
> "Home of the Rainbowfish"
> http://www.ecn.net.au/~atappin/home.htm
>