How Much Chemistry – Liquid

Using the right amount of chemistry is important to successful industrial cleaning.  Since there is no standard convention for expressing the amount of chemistry to use, it sometimes takes a little effort to sort things out.  Chemistry is supplied in either liquid or powder form with several different conventions for each.  Let’s look at liquids first.

Some typical directions are –

  • Dilute 10 to 1 with water.  Sometimes written 10:1
  • Add 8 ounces per gallon of water
  • Make a 5% solution with water or dilute 5% with water or add 5% by volume to water

The numbers above are just examples and will vary depending on the chemistry and the application.  In any event, however, you first have to know how much mixed cleaning solution you need.  Determining the volume of a tank is not difficult.

Note – For smaller tanks, it may be more convenient to work in ounces.  To convert cubic inches to ounces, divide by 1.805.

Once you know the tank volume it’s not that difficult to determine how much chemistry and how much water to use to get the right amount of the correct concentration.  The following examples will use convenient tanks sizes, not 67.32 gallons, to keep things simple.

Dilute 10 to 1 with water or 10:1 with water

Note – This one can be a little tricky since, especially in the case of the 10:1 nomenclature as it seems that 10:1 is also often written 1:10!  It is pretty safe to assume that the smaller number indicates the part that is the chemistry and the larger number is the water.

An example of what this means is that you add 10 gallons of water for each gallon of chemistry.  If you do it this way and have a 10 gallon tank, the result is that you have 11 gallons when you get done.  If what you want it 10 gallons and not 11, you have to subtract out a little bit from each constituent to end up with just 10 gallons instead of 11 gallons.  To do this accurately, you need to add the two numbers in the dilution ratio together (for the case of 10:1 it would be 10+1=11) and then divide the total volume you want by the result (10÷11=.91) and multiply the result by the number representing each constituent.  So for water it would be (.91×10=9.1 gal.) and for the chemistry it would be (.91×1=.91 gal.).  Adding .91 gal. of chemistry to 9.1 gal. of water results in 10 gal. (allowing for rounding) of a 10 to 1 dilution of the chemistry.

Add 8 ounces per gallon of water
If you have a 65 gallon tank and fill it with water then add 8 ounces of chemistry per gallon of water (520 oz. – a little over 4 gallons), you end up with a little over 69 gallons of solution when you only needed 65.  Here’s how to fix that – – Since the chemistry measure is in ounces and the water is in gallons, you first have to convert the two to the same units.  Let’s do it in gallons although if you like big numbers you can do the same thing with ounces.  To convert 8 oz. to gallons, you divide 8 ounces by 128 (since there are 128 ounces in a gallon).  This results in the amount of chemistry needed per gallon of water to be 8÷128=.0625 gallons.  Next, multiply the size of the tank (65 gallons) by the amount of chemistry needed per gallon.  The result is .0625 x 65 = 4.06 gallons of chemistry per gallon of water.  Using the same methodology as above, you add 65 + 4.06 to get 69.06.  Then you divide 65 by 69.06 to get .94 which is multiplying factor for both the water and the chemistry.  So to fill the 65 gallon tank you would need 65×.94=61.2 gallons of water and 4.06×.94=3.8 gallons of chemistry.  Voila – 65 gallons (allowing for rounding)!  Just remember, everything has to be in the same units – ounces, gallons, cups or whatever to make this work!

Make a 5% solution with water or dilute 5% with water or add 5% by volume to water
Percentages are a little simpler (I hear you sigh).  Let’s say we want to fill a 120 gallon cleaning tank with a 5% solution of chemistry in water.  In this case you need 5% chemistry and the rest water.  Chemistry is 120 gallons × 5% (5/100) = 6 gallons.  The rest is water so 120 gallons minus the 6 gallons of chemistry is 114 gallons of water.  See, much easier.

Chemistry is expensive and proper dilution is important.  Using the above will prevent using too much chemistry and keep your cleaning process under control.


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