   Return to Pool Service & Maintainance Home Page Thanks to an interested reader, (Jim Cook from Florida) I have been prompted to provide a list of words & abbreviations which I use in the Swimming Pool Chemistry sections to help you through my information.
CHLORINE - CL or CL2 A general term for the most commonly used sanitation for swimming pools, it kills bacteria, virus & algae spore & removes color, taste & odour. Chlorine in its raw form is a gas which is used in some Commercial Swimming Pool Treatment, Water Supply & Sewerage Treatment. Chlorine Gas when mixed with water forms Hypochlorous Acid the active component of chlorine mixed with water. It creats an acidic condition.
HYPOCHLOROUS ACID - The active component which is formed by the addition of any form of chlorine (including salt chlorine generation) to water. It is the Hypochlorous Acid which carries out the functions as identified in Chlorine above.
CALCIUM HYPOCHLORITE - Powder Chlorine or 65% available chlorine, sold under many lables & also in tablet form, it reacts instantly on contact with the water to form Hypochlorous Acid. Calcium Hypochlorite has a high pH in its own right & will therefore raise the pH of the water into which it is added, It will also increase the Calcium Hardness level of the water over a period of time.
SODIUM HYPOCHLORITE - Liquid Chlorine, A very common form of chlorine addition for Swimming Pools, it normally has a strength of 12.5% available chlorine, the rest being a carrier. It will instantly react with the water to form Hypochlorous Acid. Sodium Hypochlorite has a high pH & will increase the pH of the water in to which it is added.
CYANURIC ACID - A product which can be added directly to the pool water or in conjunction with some chlorines to act as a barrier to the effect which the sunlight has on breaking down the chlorine in the pool water. The Cyanuric Acid will lower the pH level slightly & it will also reduce the speed at which chlorine can react to kill Bacteria, Virus & Algae Spore. It is therefore normal to operate with a higher chlorine level when using Cyanuric Acid in a pool. A Cyanuric Acid or Stabilizer level of 30-50PPM or MG/l is normal for most pools.
SODIUM DI-CHLORO ISOCYANURATE - This is a complex powder chlorine compound which has cyanuric acid added to it to reduce the effect the sunlight has on breaking down the chlorine in the pool water. The Di-chlor will lower the pH of the pool water.
TRI-CHLORO ISOCYANURATE - This is the chlorine/cyanuric acid complex compound normally in a tablet form. The product is very often used in errosion dispensers. The product will lower the pH & Total Alkalinity of the pool water & will raise the Cyanuric Acid level over time. You will always need to superchlorinate with a calcium based chlorine to remove bacteria & algae which have built up a resistance to one level of chlorine.
BROMINE - Bromine is a complex product which has been formulated more for the spa market & hot water pools as it is far more stable at high temperatures & high pH than chlorine. Bromine has a low pH & will very quickly lower the pH & TA in the pool water.
F.A.C. - Free Available Chlorine or that chlorine which is in the form of Hypochlorous Acid in the pool water at a given point of time.
C.A.C. - Combined Available Chlorine, that chlorine which has combined with ammonia compounds (Persperation, Urine, Nasal & other body discharges) in the water. The CAC can only be removed by the addition of more chlorine. CAC is what causes sore eyes, smell of chlorine, taste of chlorine & skin rashes associated with chlorine in pools, these can only be removed by addition of more chlorine.
T.A.C. - The total of the FAC & the CAC types of chlorine in the pool.
pH - The level of the acidity of the water. pH 1.0 is very acidic, pH 14.0 is least acidic & pH 7.0 is netural. The normal level for swimming pools is between 7.4-7.7
ACID - An acid is a product which will lower the pH level of water, Hydrochloric Acid, Muratic Acid, Sodium Bi Sulphate, pH Down, pH Minus, Down pH & many other similar names.
ALKALI - An alkali is any product which will raise the pH of pool water, Soda Ash or pH Up or pH Increase are strong Alkalis, Sodium Bicarbonate & pH Buffer & the effect from Calcium Hypochlorite & Sodium Hypochlorite are weak Alkalis.
TOTAL ALKALINITY or T.A.- A measure of the Temporary Hardness in the water or the bi carbonate levels in the water, This is lowered by the addition of acid or rain or cyanuric based chlorines or Bromine. The T.A. is raised normally by the addition of Sodium Bi Carbonate or baking soda & naturally by some town water supplies. It is normal to keep a T.A. of 80-120 PPM in a pool.
CALCIUM HARDNESS - A measure of the more permenant hardness in the water, normally carbonate based products, this is raised by the addition of Calcium based Chlorines & Calcium Chloride Flake, It is lowered by dilution with rain or makeup water of a lower Calcium level. A low calcium level will lead to errosion of marcite & tile grout & pipes & cause wrinkley fingers & toes on swimmers & less efficent filtration in sand & cartridge filters. A high calcium Level will result in possible cloudy water & corrosion of any surfaces where it can deposit. It is normal to keep a level of 100-200 PPM in a pool.
TOTAL DISSOLVED SOLIDS - A measure of all the solids dissolved in the water, this should include with a good test, Carbonates, bi carbonates, minerals, & Organics which are dissolved in to the water. The higher the TDS the harder it is for the chlorine to carry out its work. A level of 500-1000 is ok.
ALKALINE - A product which is said to be alkaline normally has a pH of greater than 7.0
ACIDIC - A product which is said to be acidic normally has a pH lower than 7.0
PPM - Generally called Parts per Million but correctly pounds per million pounds - 50 pounds of calcium based product in one million pounds of water would have a Calcium Hardness level of 50 PPM. If you had only one hundred thousand pounds of water in your pool then you would have 5 lbs of calcium.
MG/L - The metric equivelent of PPM Meaning milligrams per litre
 MY SUGGESTIONS It is not hard to read the chart & using the accompanying
REMEMBER 50% of pool water problems are Mechanical, not Chemical. IF YOU HAVE ANY QUESTIONS PLEASE EMAIL TO
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