View Full Version : PP dosing calculations

Roddy Conrad
05-31-2008, 09:33 PM
Several of my ponding friends have contacted me privately recently asking for PP dosing calculations. To avoid answering a few hundred private emails and private messages on this subject, instead of giving the answers privately, I promised them to write a thread here for all to use instead.

First let me admit openly that it is better to accurately weigh PP powder on a gram scale if a gram scale that is sufficiently accurate is available. However, to buy a gram scale that is sufficiently accurate is quite expensive, because those cheap ones that claim to measure to the nearest gram really don't perform, and I find those cheap gram scales sometimes weighs 15 grams as 5 grams. So unless you have a really good gram scale that is really accurate, I suggest you simply rely on the old standard teaspoon measure. And I openly admit a teaspoon of PP powder can weigh as little as 5 grams and as much as 9 grams, but usually is fairly close to 7 grams. So I am going to state the dose both in grams and teaspoon equivalents, assuming your average teaspoon of powder weighs 7 grams.

And, NO, I am not going to do research on gram scales and their accuracy, there must be at least 100 brands of gram scales around, some actually performing as advertised, but the cheap ones usually give such misinformation a teaspoon measure is usually more accurate and trustworthy.

Okay, with that introduction, first let me state my calculation methods.

The dose will always be calculated as ppm or parts per million. Since we want the PP powder dose in grams, and the pond dose in ppm, I usually calculate the pond volume in millions of grams, then just multiply the ppm dose times the millions of grams of water to get the PP powder dose in grams. First let us do this for larger ponds that are measured in thousands of gallons, then I will take it a step further and calculate doses for small ponds and glass aquariums.

A thousand gallons of water, when the gallons are USA measure gallons (European and Canadian use a differetn gallon measure) contain 1,000 gallons times 8.3 pounds per gallon times 454 grams per pound = 3.77 million grams. So if we want a 1 ppm dose for a thousand gallons, we need 3.77 grams of PP or about a half teaspoon per 1,000 gallons. Likewise a 2 ppm dose for 1,000 gallons is 2 ppm times 3.77 million grams = 7.54 grams of the powder or about a teaspoon, 3 ppm dose for 1,000 gallons is 3 ppm times 3.77 million grams = 11.31 grams or about 1.6 teaspoons of the powder. If we want a 0.5 ppm dose, and have 1,000 gallons, then 0.5 ppm times 3.77 million grams = 1.89 grams or we need a quarter teaspoon per 1000 gallons or one teaspoon per 4000 gallons. If your pond is a multiple of thousands of gallons, simply multiply the numbers above by the thousands of gallons. Now I will post this and calculate for smaller pond and aquarium volumes.

05-31-2008, 09:50 PM
:D: Thank you Roddy

Roddy Conrad
05-31-2008, 10:02 PM
When the pond or aqurium volume is less than 1,000 gallons, it gets really tough to weigh the powder for a direct charge. So instead we make up a known weight PP solution, stir it until it is dissolved, and use a portion of the solution to get the correct PP dose.

Please be sure the container in which you make up the PP solution will not be mistaken for grape Koolaid and drunk by someone! Not a good day if that happens. Do whatever you have to do in labeling and picking the container and storage location to avoid accidents. Never put the PP solution in a refrigerator, that is guaranteeing a disaster of various kinds, the PP solution is quite stable at room temperature, don't worry about that and keep the PP solution away from any location where it might be mistaken for a refreshing drink. Label as a PP solution and state on the label it is dangerous, PLEASE. Do NOT use a metal lid, the PP solution will eat through metal rather quickly. When and if you need to dispose of it, I suggest you simply pour it on the ground outside and wash the area with a hose.

Okay, so much for the cautions, and they are worth considering, for storage of PP solutions. They are stable, but must not contact metals, and must be labeled, and kept away from children and idiots who don't comprehend chemicals and their effects.

Now to the instructions.

Choose a liter or quart container that is plastic or glass with a lid that is plastic or glass.

In the container add one teaspoon or 7 grams weighed PP powder. Add water to half full, put on the cap, shake it around until the powder is dissolved, wear rubber gloves, be careful to avoid getting the solution on you or your clothes. When the powder is dissolved, take off the lid and fill the container, we first only filled it half full so there was some room to agitate the solution. Mix it a little to make sure the solution is uniform.

Now we have a solution of 7 grams of PP in 1000 grams of 0.007 grams per milliliter of the solution.

Now lets calculate the amount of this solution for a 10 gallon aquarium for the variety of doses that may be of interest, specifically 0.5 ppm, 1 ppm, 1.5 ppm, and 3 ppm. 0.5 ppm is for water cleanup, 1.5 ppm is for parasite control, ulcer cleanup, and fin rot cures. 3.0 ppm is for stronger parasite control.

A 10 gallon aquarium contains 10 gallons times 8.3 pounds per gallon times 454 grams per pound = 37,682 grams of 37.7 thousand grams or 0.0377 million grams. If we want a 0.5 ppm dose, we then need 0.5 ppm times 0.0377 million grams = 0.019 grams of PP. We calculate our solution has 0.007 grams per milliliter, so 0.019 grams divided by 0.007 grams per milliliter = 2.7 ml (milliliters) dose of the solution described above to put a 1 ppm dose in a 10 gallon aquarium. Likewise, for a 100 gallon pond or aquarium tank, since 100 gallons is 0.377 million grams, for a 1 ppm dose in 100 gallons we need 1 ppm times .377 million grams = 0.377 grams; divide 0.377 grams by 0.007 grams per milliliter and we calculate we need 54 milliliter of the solution described above for a 1 ppm dose in 100 gallon pond, quarantine tank, or aquarium.

How many more examples do we need? Ask questions please. For my buddy who asked, for example, a 30 gallon aquarium is 30 gallons times 8.3 pounds per gallon times 454 grams per pound = 113,046 grams or 0.11 million grams. A 1 ppm dose is then 0.11 grams of PP, divide that by 0.007 grams per milliliter and we calculate we need 16 ml of the solution for a 1 ppm dose for 30 gallons, or 24 ml for the 1.5 ppm dose I recommended to cure the fin rot in the tank of fancy goldfish. And you said the repeat doses (using that exact solution formula and dose calculation protocol) every few days did clear the fin rot when nothing else you had tried for a few months did any good for the problem. And the reason you wanted a record is that I did the calculation in my head as we chatted on the phone and you did not have confidence you could get the decimal points just right without a record in writing to check yourself.

I suspect others don't have the developed "in the head" math skills either I carry around, so here it is as requested.

Seriously, if some of youneed more examples to "get it", just ask, but ask in public so others can learn with you and print it off or store it electronically for future use.

Roddy Conrad
05-31-2008, 10:09 PM
Postscript: When you mess up and get a PP solution on you, or spill the powder on you, as I have done many times, please consider these actions.

First brush off any powder before doing anything else! The powder will burn but will burn faster when wetted, so before washing brush off the powder. Then flush with water rapidly and well. Then as soon as possible wash the area with 3% hydrogen peroxide, which usually avoids a large brown stain on your skin if you do it quickly and well. Sometimes the 3% peroxide will remove a brown stain that has developed on your skin, sometimes it is not so effective. The skin is oxidized in much the same way as a sunburn, and will heal quickly if it is not a deep burn. PP only oxidizes, it is not a carcinogen or anything like that.

If PP gets on the clothes, simply throw them away. You will be unable to get the brown stain out of the clothing, no point in messing up trying to save any clothing with a PP stain. Not possible.