Your swimming pool water collects minerals over time, causing "Parts-per-million" to exceed recommended levels. When this happens, many things start to go wrong with your pool, such as the inability to balance chemicals, buildup on pool tile, and water that makes your skin itchy. To best deal with this problem, we recommend a drain and fill every 3-5 years. Does this sound like your pool? This is also a great opportunity to have your pool surface acid washed and/or your pool tile professionally cleaned.