The green corrosion in soft water comes from the copper pipes. It’s something you need to treat as soon as you notice it. By treating it you’ll eliminate it, but you also need to take appropriate steps to make sure it doesn’t return. Corrosion in soft water is quite common. It can leave stains on plumbing fixtures and even on clothes. Eliminating it can be a task, but it’s a worthwhile one.
Step 1 - Corrosion
The green corrosion you see in soft water is actually the metal dissolving in the water. The metal is from the copper pipes in the system. The corrosion can have many different causes, although as a general rule it’s because of a reaction between the water and the pipes.
Step 2 - Causes
The causes of the corrosion could be something like sand in the pipes taking off the metal or the fact that the pipes weren’t installed and de-burred properly. If electrical appliances haven’t been grounded properly to the copper piping, this can also cause corrosion. You’ll find that low pH in the water can also cause corrosion. Generally you won’t find this in municipal water systems, though.
Step 3 - pH
You need to examine the soft water pipes to try and establish the cause of the corrosion. This will allow you to treat the problem properly. The easiest way to begin is to use a pH tester on the water to be sure it’s not low. If it is, take steps to alter the pH and see if this stops the corrosion. To do this, install a calcite neutralizer tank. This will increase the alkalinity. It will also raise the pH to 8.0. You can use a soda ash feeder instead; it will perform exactly the same function.
You fill the neutralizer tanks with a mixture of calcium carbonate and magnesium carbonate. You should only need to add more once each year. Both of these are minerals that occur naturally. When they dissolve in the water they lower the corrosion level.
Step 4 - Visual Inspection
From there you’ll need to examine the pipes visually. You want to check to see that the pipe system has good electrical continuity and that no unnecessary wiring is connected to the system. You also want to check the soft water pipes to be sure they’re properly grounded. If they’re not, install a proper ground; this will help eliminate the green corrosion in the soft water.
Step 5 - Curing the Corrosion
If you can’t find any obvious cause for the soft water corrosion, you can take other steps to remove it from your system. The ideal way to do this is by installing a phosphate feeder. It should be added to the system before the copper piping starts. It releases phosphates that leave a coating on the piping. This has the effect of slowing the effects of corrosion. The phosphate coating acts as a form of insulation on the copper pipes.