b'Pool Cheat Sheet pH (Continued) Above pH 7.8 conditions also become very favourable for algae blooms. Maintaining pH in a pool is therefore critically important, as it aids sanitation, swimmer comfort & equipment lifetime whileoptimising running costs. Pool Magic Soda Ash is used to raise pH levels, while Pool Magic Hydrochloric Acid or Pool Magic Dry Acid is used to reduce them. Total Alkalinity Total alkalinity is a measure of the alkaline substances in the water. The level of TA in a pool should be kept between 80 - 150ppm, allowing for variation depending on pool surface type. Within this range, TA acts as a buffer that prevents the overall pH to rocket upwards or downwards wildly. Think of it as a seatbelt that holds your pH in place & optimises chlorine efficiency. The effects of TA being too low are: pool surfaces can etch, metals can corrode, floor & walls can stain, water can turn green & eyes can burn. The effects of TA being too high are: the pH becomes hard to adjust lower, the water becomes cloudy, tests will show a constant need for acid, & chlorine can become less effective. Pool Magic Buffer is used to raise the TA level, while Pool Magic Hydrochloric Acid or Pool Magic Dry Acid will lower it. Calcium Hardness Calcium hardness relates to the calcium mineral content of the water. Hardness levels should be kept between 180-350ppm, allowing for variation depending on the pool surface type. Recall that optimal chlorination happens at pH 7.2 - 7.6, and that we want Total Aklinity to buffer the pH at that level. However, at those levels it triggers a demand - think of it as a thirst - for calcium in the water. If you have a calcium- rich marblite pool surface, then the water will try scavenge calcium from the walls, causing surfaces to etch, & metalsto corrode. Optimal calcium hardness prevents imbalance & quenches this calcium thirst. On the other hand, if the calcium levels are too high, the water will expel it from solution - causing calcium-scale precipitate to form around the pool. Filters & pipes may clog, water can become cloudy & eyes may burn. Pool Magic Calcium Increaser is used to raise the level, but lowering generally involves draining water,& topping up with fresh water. Pool Cheat Sheet Salinity Salt pools use ordinary table salt (NaCl) to generate free chlorine / HOCl in pool water via electricity. Salinity (salt) refers to the salt level of a pool. Salt levels will vary depending on the ranges specified by the salt chlorinator installed on the pool. A chlorinator will operate mostefficiently when the salinity is within the specified ranges. In extreme cases, you can cause damage to the salt cell in the chlorinator, and other pool hardware if the salinity is outside of these ranges. It can also lead to an unsanitary swim environment if the levels are too low, as there wont be enough chlorine being generated, which in turn leads to algae growth. Adding swimming pool salt will raise your salinity levels, but the only way to lower salinity levels is to drop the pool level & top up with fresh water. Total Dissolved Solids (TDS) Total dissolved solids (TDS), is a measure of the total of all soluble substances dissolved in the water. It is usually measured by assessing the electrical conductivity of the water, which can be achieved with a 2-prong salt tester (the tester will have a TDS function). For a fresh water swimming pool, the maximum recommended TDS level is 2000ppm. Higher levels can lead to cloudy water, staining, scale build up, and a salty taste. In a pool using a salt chlorinator, TDS levels are made redundant by the addition of the salt, which increases the TDS levels greatly. There is no effective way to reduce TDS without replacing some or all of the water. Free Chlorine The presence of chlorine is not a sign of disinfection capability. Whatever the source of chlorinemolecules (e.g. salt, chlorine gas, liquid chlorine or solid chlorines like calcium hypochlorite orTrichlor), in solution they all combine with water to form the disinfectant Hypochlorous acid (HOCl). Only Free chlorine will form the Hypochlorous Acid (HOCl) you need to kill bacteria & viruses, and oxidise away contaminants & waste products. To both sanitise an oxidise a pool, Free Chlorine Residual of at least 1ppm is required at the correctpH (see pH below) When free chlorine combines with the organisms & contaminants (urine, sweat, make-up,hairspray, etc) its job is done, and it becomes combined chlorine. However, when water conditions are not optimal, chlorine levels are too low or when bather loads & other waste levels are too high, it can prevent Free chlorine from forming HOCl. Instead, the chlorine combines with waste & other chemicals to form compounds that are not effective disinfectants. Combined Chlorine Combined chlorine - the opposite of Free chlorine - has minimal sanitation & oxidising capability. Total Chlorine Total chlorine is the sum of both free & combined chlorine. Ideally the total chlorine reading should equal the free chlorine reading (known as breakpoint chlorination). pH pH, or potential hydrogen, is measured on a scale of 0-14, with 7 being neutral. Solutions lower than 7 are referred to as acidic, & solutions higher than 7 are referred to as alkaline. The pH of water determines how effective chlorine will be. Free chlorine will form the maximum possible amount of hypochlorous acid (HOCl) disinfectant at pH 7.0 & below. However, below pH 7.0, chlorine becomes too aggresive (staining) & volatile (loss to atmosphere) for swimming pool use. Therefore, the ideal recommendation for pH in a pool is 7.2 - 7.6 on the scale - low enough to optimise Free chlorine / HOCl formation without risking unwanted adverse effects. Cyanuric Acid (Stabiliser) UV rays from the sun steal chlorine from pool water. So after a long days sunshine chlorine levels may fall, then rise again overnight & fall again in the day. To combat this natural zig-zag instability in chlorine levels we add a chemical that has a strong affinity for chlorine, that is able to hold onto it & prevent the UV rays from stealing quite so much. This chemical is called Cyanuric Acid but because of its purpose, it is commonly referred to as Stabiliser. Think of stabiliser as a sunscreen for a pool. UV light degrades chlorine at twice the rate without stabiliser present in the water. Stabiliser levels should be kept between 30-50ppm, However, excessive stabiliser is counter-productive. At levels exceeding 2100ppm, theres so much stabiliser that it interferes with the formation of Free chlorine - and therefore HOCl - causing it to work slower. This is commonly known as Chlorine Lock. Pool Magic Fast Dissolving Stabiliser is used to raise the stabiliser levels. Dropping the pool level is the most effective way to lower stabiliser levels. To overcome Chlorine Lock it is necessary to either drain a percentage of pool water & top up, or to use a biological cyanuric acid remover. Phosphates Phosphates are a key plant food/fertiliser - & algae therefore thrives on it. Runoff from ground water, decayed plant matter, acid rain, sweat, urine & bird droppings can increase the phosphate levels. Even swimming clothes washed in detergents containing phosphates can raise the level. Phosphates are made up of plant nutrients, that algae require to grow. Even low levels in a pool can accelerate algae growth without proper maintenance. Phosphates can be tested for on a 201 series spin disk, or with a phosphate test kit. To remove phosphates, use the Pool Magic Phosphate Remover or Pool Magic Phos-Tabs (NEW) 179'