PPM....(parts per million)

[faka4u]

hi, good day lovely reefers. I'm Stephen, new here and first post.
pls i want to understand the meaning of 2ppm. like when we say dosing 2ppm of calcium.
i tried checking for the actual meaning on youtube and google, didn't get anything more than 2 parts in 1 million, which is still not explanatory enough for me to comprehend...anyone who can help pls?thanks.

 

[Ron Reefman]

First, welcome to R2R!

All it means is that in a million atom sample of that water, 2 of the atoms will be calcium. It doesn't matter that the other 999,998 atoms are. Some will be hydrogen, some oxygen, some other elements, but 2 will be calcium.

I hope that helps.

 

[piranhaman00]

ppm is parts per million or mg/L or ug/mL, since most hobbyist can measure ug accurately lets stick to mg/L. I will just run through an example of how I use it, hopefully helps.

I want to dose NO3 (Nitrate) into my aquarium. I made a solution using KNO3, 100 grams of KNO3 into 1L of DI water. Now you need to know how to convert between units, metric rules because its all factors of 10, I live in the US and cant stand our units but different story. My solution is now 100g/L, which is the same as 100,000mg/L (100 grams * 1000 = mg) or 100,000ppm. Now my aquarium is 500L. A great forumula is C1*V1=C2*V2 where C= Concentration and V= Volume. I input my known values into the formula.
C1=Known concentration of solution, 100,000ppm NO3
V1= Unknown volume
C2=What I want to raise my concentration (2ppm for example)
V2= Volume of aquarium in L.

100,000ppm * V1 = 2ppm * 500L

Solving this formula will show how much 100,000ppm solution is required to raise 500L of water 2ppm NO3 . Solving gives us 0.01, ppm units cross out giving 0.01L of solution, multiply by 1000 to get mL, 10mL.

So 10mL of our 100,000ppm solution will raise a 500L aquarium 2ppm NO3.

This is very useful, I use it frequently!

Gosh now I miss analytical chemistry! Never knew that course would help me with a future hobby

Hope this helps!

 

[Larry L]

new here and first post

Welcome!

i want to understand the meaning of 2ppm. like when we say dosing 2ppm of calcium.

Think of ppm (parts per million) like a really small percentage. 1% means one part per hundred, so 1 part per million is 10,000 times smaller than that.

Suppose you want to keep your Calcium levels at 420 ppm, that's kinda like saying your water is 0.042% Calcium. If your tank consumes 20 ppm Calcium over the course of a week, then it would end up at 400 ppm, or 0.040% Calcium.

So if someone says they are dosing 20 ppm Calcium per week, that just means they are dosing however much Calcium is needed for their tank's water volume to bring it back up from e.g. 0.040% Calcium to 0.042% Calcium (i.e. from 400 ppm to 420 ppm).

 

[beaslbob]

Perhaps already stated, but I think the PPM is weight based. so 2 parts per million of a pound of stuff means 2 millions of a pound would be the 2ppm stuff.

This is contrast to molar which is based on particles like atoms/molecules.

perhaps others can chime in and correct anything I misunderstand.

my .02

 

[dbjonesjr]

To clarify what others have said, “ppm” as we use it in the reef aquarium hobby refers to parts per million by mass. There are other ways to use “ppm” such as volume or moles, but those aren’t the standard for communication in the hobby.

As a little bit of an explanation, much like provided above, 1 gram of Magnesium in 1000000 grams of water is equal to 1 ppm. When we refer to mg/L, that is mainly because we don’t have a good way to measure weight of the water in our tanks, so we use the standard conversion that 1kg=1L, even though this isn’t always the case.

I should mention that if you want to make a solution you need to take into account the mass of something like Potassium within Potassium Nitrate.

 

[Randy Holmes-Farley Verified Community Expert]

So clarifying again, 2 ppm can be any units. Mass, usually, for in tank things, but not necessarily mass for things in air, where it is more often partial pressure/molecule based.
Also, ppm does not equal mg/L in seawater because 1 L of seawater weighs more than one million milligrams. Most people use them interchangeably, but they are different by about 2.5%.

 

[Randy Holmes-Farley Verified Community Expert]

Thus article of mine details about every unit of measure used in Reefing:

http://reefkeeping.com/issues/2005-08/rhf/index.php

 

[vetteguy53081]

 

[Silent]

Welcome and what he said.

 

[faka4u]

First, welcome to R2R!

All it means is that in a million atom sample of that water, 2 of the atoms will be calcium. It doesn't matter that the other 999,998 atoms are. Some will be hydrogen, some oxygen, some other elements, but 2 will be calcium.

I hope that helps.

thanks, you have done justice to it.

 

[faka4u]

ppm is parts per million or mg/L or ug/mL, since most hobbyist can measure ug accurately lets stick to mg/L. I will just run through an example of how I use it, hopefully helps.

I want to dose NO3 (Nitrate) into my aquarium. I made a solution using KNO3, 100 grams of KNO3 into 1L of DI water. Now you need to know how to convert between units, metric rules because its all factors of 10, I live in the US and cant stand our units but different story. My solution is now 100g/L, which is the same as 100,000mg/L (100 grams * 1000 = mg) or 100,000ppm. Now my aquarium is 500L. A great forumula is C1*V1=C2*V2 where C= Concentration and V= Volume. I input my known values into the formula.
C1=Known concentration of solution, 100,000ppm NO3
V1= Unknown volume
C2=What I want to raise my concentration (2ppm for example)
V2= Volume of aquarium in L.

100,000ppm * V1 = 2ppm * 500L

Solving this formula will show how much 100,000ppm solution is required to raise 500L of water 2ppm NO3 . Solving gives us 0.01, ppm units cross out giving 0.01L of solution, multiply by 1000 to get mL, 10mL.

So 10mL of our 100,000ppm solution will raise a 500L aquarium 2ppm NO3.

This is very useful, I use it frequently!

Gosh now I miss analytical chemistry! Never knew that course would help me with a future hobby

Hope this helps!

yes it did really....thanks