There are very few reasons why a person should need to drain their pool. In reality, emptying the pool is risky and can cause significant damage. Thanks to improved technology in the industry, pool owners now have alternative water treatment options to help prevent drainage hazards. As a result, residential pools can last longer than ever.
Swimming pools are designed to be filled with water and are not structurally sound when empty. When a pool is drained, three untoward things can happen. For starters, the shell will burn every time it is drained. Gypsum pools are especially notorious for becoming porous the more often they are drained. This gives rise to algae growth and sometimes the only way to repair this damage is to re-cast. The second risk is cracking or bursting of the shell. This can happen in both plaster and pebble pools. Sections of the shell may come off and fall off, and small or large cracks may appear. The third risk is due to hydrostatic pressure that can build up under the pool. When the pool is empty and the pressure is higher below the pool than above the pool, everything can lift/float off the ground. In this case, the damage is usually irreparable. These risks can be completely avoided by choosing the right water treatment. Understanding the reasons why a pool should be drained and the alternative options available is the first step in preventing undue damage.
Green pool water does not need to be drained. This is the most common reason pools are drained unnecessarily. The factors that contribute to the growth of algae are the lack of chlorine and the abundance of phosphates in the water. Once these two things have been taken care of, with a quality algaecide and a phosphate remover, the water should return to its normal state. For the most part, a decent pool with a working filter should be able to clean even the greenest of water on its own. It will take time, attention, and the right chemical balance, but green water can almost always be transformed into crystal clear water without draining.
High levels of combined chlorine, sometimes referred to as chlorine lock, is a phenomenon that can occur. When chlorine added to water does not have the desired disinfecting effect, it is usually due to combined chlorine. A common characteristic that denotes it is the strong “chlorine smell” that is detected around the pool. When cyanuric acid levels exceed 80 ppm, or when the PH is out of balance, there is an increased risk of this happening. A common condition is that the chlorine will molecularly bind cyanuric acid and other unwanted chemicals and not leave enough free chlorine to destroy organics in the water. Traditionally, the only way to remove cyanuric acid is to drain and fill. Thanks to recent advances in pool care techniques, it is possible to extract cyanuric acid and combined chlorine from the water without draining it. Reverse osmosis is sometimes used to accomplish this. Ion exchange treatment units will also remove contaminants from the water and eradicate chlorine blockage. This is achieved by recycling the water through activated carbon filters in conjunction with ion exchange units.
Substances that cause hardness combine over time with evaporation and chemicals added to the water. High levels of hardness cause damage to swimming pools. Evidence of high calcium levels can be seen in the white deposits on the tiles around the pool’s water line. If the calcium is especially high, calcium deposits can form underwater on the shell of the pool. If the calcium gets too high (over 500 ppm) and leaves deposits, it may be necessary to hire a tile cleaning company to remove scale around the water line and drain areas. If calcium nodules have formed underwater, the pool may need to be chipped and re-plastered. It is much better to avoid these problems by keeping calcium levels low. A common and outdated method of reducing calcium levels is to drain the pool and refill it. As mentioned above, this is potentially dangerous and can cause damage. The same alternative “no drain” methods used to reduce cyanuric acid levels are also effective in reducing calcium hardness.
Given the risks involved in draining, the only legitimate reason to do so is to repair submerged components or acid wash the interior of the pool. Even these procedures can be performed without drainage in most situations. Nowadays, it is safer and smarter to avoid the risks of emptying the pool completely and to choose a risk-free alternative.
The first of the two alternatives to drainage is reverse osmosis. Reverse osmosis in a swimming pool is done by passing the water through a large reverse osmosis system housed in a trailer. The water is recycled back into the pool free of cyanuric acid and unwanted chemicals. Calcium levels can also be reduced to a lower, more balanced range. The downside: It doesn’t hold all the water, and some of it is lost in the process. It’s also a bit pricey for most pool owners.
The second alternative to drainage is ion exchange. Ion exchange employs the use of commercial grade water softeners in conjunction with activated carbon filters to filter out contaminants and hardness. The water is recycled through a system that is usually installed next to the pool and works silently for around 12 hours. All the water is preserved and the unwanted chemicals are removed along with the calcium harness and cyanuric acid. Calcium hardness is reduced to 150 to 200 parts per million leaving the pool with sparkling healthy water. This treatment is more affordable than reverse osmosis.