Clean Sweep: Expert Advice on Maintaining Your Pool or Hot Tub

Keep out the green stuff
Poorly maintained pools are ideal for algae growth. Yellow-green blotches, black spots, and green patches develop on pool surfaces when algae spores in the air settle in the pool water. Algae can be removed by brushing and scrubbing affected areas and adding an algaecide directly to the water near the algae growth. Future algae growth can be prevented by maintaining proper water balance, shocking the pool regularly, as well as by using special algaestats or algae preventatives.

Dissolved metals such as ion, copper, and manganese, which can stain pool surfaces, can cause pool water to turn a green or greenish-blue tinge. To remove stains and clear up discoloured water, special sequestering agents can be added that tie up metallic ions.

Grey, white, or brown scaly patches can also develop on pool surfaces. These are caused by excessive calcium in the water and can be eliminated by adding a special sequestering agent that holds calcium in solution—preventing it from precipitating out of the water and settling on pool surfaces.

The best way to prevent calcium deposits, algae, and staining is to properly maintain pool water balance. Maintaining properly balanced water not only makes your pool or hot tub safe to use and improves the appearance of the water, it also prevents damage to pool and hot tub surfaces, keeps the plumbing clear of calcium buildup, and extends the life of the filter, heater, and pump.

The following are the main levels you should test for in your pool:

Sanitizers—For bather health and safety, the most important level to measure is the active pool sanitizer (disinfectant) level in the water. Both chlorine-based and bromine-based products are effective sanitizers that reduce the amount of harmful micro-organisms, bacteria, and organic matter in the water, making it safe for bathers to use. The recommended chlorine (or equivalent bromine) sanitizer level should be maintained at 1-3 ppm (parts per million).

pH—Another important parameter to measure is pH. This test will let you know whether the pool water is acidic, neutral, or alkaline. Ideally, your water should have a pH of 7.4-7.6. When the pH is too low (below 7.2), the sanitizer level in the water dissipates more rapidly and pool and hot tub surfaces and metal components may corrode. When it is too high (above 7.8), sanitizer efficiency is reduced, scale begins to form and the water will become cloudy. Testing the pH level will let you know which type of pH adjusting products you need to add to the water.

Total alkalinity—Total alkalinity (TA) measures the amount of alkaline salts in the water, which has an effect on the pH level of the water. Pools with a low TA level (under 80 ppm), will allow the pH to swing rapidly back and forth from high to low levels, which in turn can damage vinyl, paint, and plaster surfaces of the pool, as well as corroding metal fittings and leaving stains on pool surfaces. Pools with a high TA level (above 120 ppm) make adjusting the pH difficult and can cause the water to become cloudy. The proper TA range for pool water is 80 to 120 ppm.

Calcium hardness—Pool water with a low calcium hardness level can damage concrete surfaces by leaching the calcium from the concrete, while high calcium levels can increase the formation of scale. Pool water should therefore be maintained with a calcium hardness level of 200 to 240 ppm.