1 00:00:00,560 --> 00:00:03,600 Speaker 1: Welcome to brain Stuff from how stuff works dot com 2 00:00:03,600 --> 00:00:08,240 Speaker 1: where smart Happens. Hi, I'm Marshall Brain with today's question, 3 00:00:08,720 --> 00:00:12,879 Speaker 1: how does a water softener work? We call water hard 4 00:00:12,960 --> 00:00:16,160 Speaker 1: if it contains a lot of calcium or magnesium dissolved 5 00:00:16,160 --> 00:00:20,000 Speaker 1: in it. Hard water causes two problems. First, it can 6 00:00:20,040 --> 00:00:23,959 Speaker 1: cause scale to form inside of pipes and water heaters 7 00:00:24,000 --> 00:00:27,800 Speaker 1: and tea kettles. The calcium magnesium participate out of the 8 00:00:27,800 --> 00:00:33,320 Speaker 1: water and stick to things. Eventually pipes can become completely clogged. Second, 9 00:00:33,360 --> 00:00:36,440 Speaker 1: the calcium and magnesium react with soap to form a 10 00:00:36,520 --> 00:00:40,520 Speaker 1: sticky scum and also reduces the soaps ability to lather. 11 00:00:40,960 --> 00:00:43,400 Speaker 1: Since most of us like to wash with soap, hard 12 00:00:43,440 --> 00:00:46,839 Speaker 1: water makes a bath or a shower less productive. The 13 00:00:46,920 --> 00:00:49,760 Speaker 1: solution to hard water is either to filter the water 14 00:00:49,880 --> 00:00:54,360 Speaker 1: by distillation or reverse osmosis to remove the calcium and 15 00:00:54,400 --> 00:00:58,720 Speaker 1: magnesium altogether, or to use a water softener. Filtration would 16 00:00:58,720 --> 00:01:01,320 Speaker 1: be expensive to use or all the water in a house, 17 00:01:01,400 --> 00:01:05,160 Speaker 1: so a water softener is usually the less expensive solution. 18 00:01:05,800 --> 00:01:09,480 Speaker 1: The idea behind a water softener is simple. The calcium 19 00:01:09,480 --> 00:01:13,399 Speaker 1: and magnesium ions in the water are replaced with sodium ions. 20 00:01:13,800 --> 00:01:17,240 Speaker 1: Since sodium does not precipitate out in pipes or react 21 00:01:17,280 --> 00:01:20,399 Speaker 1: badly with soap. Both the problems of hard water are 22 00:01:20,480 --> 00:01:24,679 Speaker 1: completely eliminated. To do the ion replacement, the water in 23 00:01:24,680 --> 00:01:28,240 Speaker 1: the house runs through a bed of small plastic beads 24 00:01:28,560 --> 00:01:32,319 Speaker 1: or through a chemical matrix called zeolite. The beads or 25 00:01:32,400 --> 00:01:36,240 Speaker 1: zeolite are covered with sodium ions. As the water flows 26 00:01:36,360 --> 00:01:39,880 Speaker 1: past the sodium ions, they swap places with the calcium 27 00:01:39,880 --> 00:01:44,199 Speaker 1: and magnesium ions. Eventually the beads or zeolite contain nothing 28 00:01:44,240 --> 00:01:47,880 Speaker 1: but calcium and magnesium and no sodium, and at this 29 00:01:48,000 --> 00:01:51,800 Speaker 1: point they stop softening the water. It's then time to 30 00:01:51,960 --> 00:01:57,400 Speaker 1: regenerate the beads or zeolite. Regeneration involves soaking the beads 31 00:01:57,480 --> 00:02:01,240 Speaker 1: or zeolite in a stream of sodium ions. Salt is 32 00:02:01,320 --> 00:02:05,000 Speaker 1: sodium chloride, so the water softener mixes up a very 33 00:02:05,080 --> 00:02:09,080 Speaker 1: strong Brian solution and flushes it through the zolder beads. 34 00:02:09,520 --> 00:02:11,560 Speaker 1: This is why you load up a water soften or 35 00:02:11,600 --> 00:02:16,160 Speaker 1: with salt crystals. The strong Brian displaces all the calcium 36 00:02:16,160 --> 00:02:18,880 Speaker 1: and magnesium that is built up on the beads and 37 00:02:18,919 --> 00:02:23,280 Speaker 1: replaces it again with sodium. The remaining Brian plus all 38 00:02:23,320 --> 00:02:26,800 Speaker 1: the calcium and magnesium is flushed out through a drain pipe. 39 00:02:27,160 --> 00:02:31,040 Speaker 1: Regeneration can create a lot of salty water, something like 40 00:02:31,120 --> 00:02:35,040 Speaker 1: twenty five gallons for each cycle. Do you have any 41 00:02:35,080 --> 00:02:38,760 Speaker 1: ideas or suggestions for this podcast? If so, please send 42 00:02:38,760 --> 00:02:42,040 Speaker 1: me an email at podcast at how stuff works dot com. 43 00:02:42,160 --> 00:02:44,440 Speaker 1: For more on this and thousands of other topics, go 44 00:02:44,560 --> 00:02:48,320 Speaker 1: to how stuff works dot com.