I tried 3 magnetic softeners. Two of them failed to do anything and I returned them. The third worked just great and I'm happier with it than I was with my old water softener that kept breaking down. So yes, a magnetic water conditioner can work as well as a big expensive water softening system BUT most of the ones on the market don't. Why? Because they are cheap ripoffs that just want to take your money for nothing, just like all those other scams you find online. And how do you know the difference? Well the rule is NEVER buy one which does not have a good return policy because most of them don't work.
There is scientific evidence about the effectiveness of magnets in treating hard water. Not only do they prevent scale from forming, they also can breakup and clear scale that has built up in your home, which is something that regular water softeners cannot do. This scientific evidence is both good and bad. It is good because it provides an inexpensive way of treating hard water. It is bad because now everyone with a magnet is trying to sell a solution for hard water and claiming that it works. So clearly there are a lot of wannabe's out there. Try it yourself. Get a magnet, as strong as you can find, and put it on a water pipe and open your faucet. Do you notice a difference? Of course not! The thing is that the scientific evidence that you find out there refers to very strong magnetic fields which most magnets cannot produce. The big industrial magnets work, but smaller ones that are sold all over the internet are practically useless. That is not to say that none of them work, because the one I tried (Z78) works for me. But I think it is the exception to the rule because none of the others I tried did anything to soften my home water. The Z78 uses a patented technology which greatly increases the power of its magnetic field. It is based on having a directional flux for the magnet. I really don't understand the science behind it, but it works when others don't.
It is important also to keep in mind that, technically, magnets are hard water conditioners, not water softeners. Soft water refers to water from which calcium and magnesium have been removed. It is also called soft water because of the sodium in it which gives it a silky, sometimes even slimy feel. Magnets alone (i.e. without a specialized filter) do NOT remove calcium or magnesium or any other minerals or chemicals from the water. Magnetic softeners create a magnetic field around a section of the water pipe which charges water molecules and mineral ions to make them behave in a "soft" way. Please refer to the water conditioning section for more information about how magnetic fields work to treat hard water.
You will find a lot of magnetic devices for water treatment. Most of them are just sold on Amazon or eBay and you really can't find much information about them or their brand. That in itself should be a clue about their reputation. I tried 3 different brands. The only one that worked properly was the Z78. I'm not going to say which ones did not work because of the threats I received earlier. Keep in mind that you will need 2 units of the magnet, one for the cold water pipe and one for the hot water pipe. Here are some common ones with their prices:
My advice is if you want to get a magnetic water softner, then make sure that there is a good return policy. Also, it is best if you know someone who tried so you can know it is effective. There are many many ones online now sold for very cheap. But remember that magnet trick I taught you ... a regular magnet just won't do the trick.