Saline Pool Staining:

Salt chlorine generators have changed the way many pool owners sanitize their pools.  Although the technology has been around for two decades, it is the last 5 years that chlorine generator sales have skyrocketed, driven mostly by the high cost of chlorine.  Many customers experience some degree of staining because of two major factors in a salt pool.  The first is caused by galvanic corrosion, the second is from improper water balance including high levels of phosphate in the water.

The first issue, galvanic corrosion is caused when two or more dissimilar metals are introduced into the water.  In the case of a salt chlorine system, titanium is the introduced by the plates of the generator cell.  When a pool is built, it may have other metals introduced from the light fixture, rail cups, escutions, steel screws, and a big one the copper exchanger in a pool heater.  As the metals corrode, they will leave stains in the pool like green or black stains on the light ring, plaster, or escutions.  Sometimes black flecks will be found in the bottom of the pool indicating the copper exchanger in the heater is being sacrificed and deposited via the returns to the pool.

How to eliminate this is relatively simple.  By introducing a metal that is more anodic than any of the other metals in the pool, it will sacrifice itself before corroding steel or copper.  The metals that reside further out on the anodic scale are zinc and magnesium.  By introducing a self sacrificing plate made of zinc will solve the staining and corrosion problem in a salt pool.  Most pool service companies and builders can install one for a reasonable cost.

The second issue, water balance, phosphates, and impurities in the pool can cause a myriad of problems with staining and algae growth.  Most people that own a pool are aware of maintaining Ph, chlorine, calcium hardness, alkalinity, cyanuric acid, and salt level.  But we find that the aggravating staining and persistent algae growth can be caused by high levels of phosphates.  When water is tested, it should be also tested for phosphates.  if the phosphate level is above 150 ppb, a good phosphate remover is required.  If metal staining has occurred in the pool and a metal stain remover is added, make sure that is a phosphate free product, many of them do have phosphates in them.

The last item that contributes to staining is impurities introduced to the pool water.  This can happen when a lesser grade of pool salt is added to the water.  Products that are purchased from Home Depot, Lowe's, or Costco tout that they are 99% pure.  Well on a 22,000 gallon pool you have to put about 530 pounds of salt.  So that means that 5.3 pounds of impurities are thrown into the pool along with the salt.  A good pool salt is refined and has no impurities to stain the pool, it costs a little more but fighting stains will ultimately cost a lot more to eradicate.

Follow these simple steps to a stain free pool and swim season will be a pleasure.