Watermaid is going for comfort.  Our body salt level is about 9000 parts per million.  In fact the first 9 months of our existence we swam around in a 9000 parts per million pool ( moms tummy).  We have some therapy pools (most are medical facilities) that actually run a perfect isotonic solution of 9000 parts per million.  The down side to that is it will taste like  tear.  For most pools Watermaid runs a salt level of 6000 parts per million.  The water isn’t as salty but then again it isn’t quite as comfortable either.  Watermaid doesn’t usually go lower than that for a couple of reasons.  First you are loosing comfort by going lower and a lower salt level will see a constant pH drift.  By holding a higher salt level you don’t split as much water and drive off hydrogen which pushes pH up.
Other manufacturers run a lower salt level because it is cheaper to produce the power supply.  At higher salt levels there is considerable load on the power supply and it needs to be built to take that, and it costs money.
They defend themselves by claiming that they are less corrosive and you can save on salt.  The reality is, a 6000 parts per million solution is 1% less corrosive than a 3000 parts per million pool because there is less oxygen in solution at 6000 parts per million.  You also need to keep everything in perspective.  6000 parts per million sounds like a huge number.  In fact it is slightly more than 1/2 of 1%.  a 3000 parts per million solution is slightly less than 1/2 of 1%.
We swim in our pool for enjoyment.  For that reason we heat it and keep it clean.  We feel that salt level is a huge part of pool comfort.  If you get a chance to swim in a 6000 parts per million pool compared to a pool that runs lower salt levels, We are sure that you will understand why we do it.