In a salt-water pool (a pool using a chlorine generating system), as the salt dissolved in the water passes through the plates of the chlorine generating cell it is broken apart in order to sanitize the swimming pool. When the salt is dissolved in the water there is a loose bond between the NaCl and the H20. When the solution passes through the cell, the chlorine is negatively charged and the Na is positively charged. Then the Cl attracts itself to another Cl forming Cl2.
The Cl2 cleans the pool – and it is very erratic. It breaks apart into two separate chlorine parts; that is what eliminates contaminants. The chlorine then tries to find the stable Na ion and reconnects to reform NaCl.
There are plenty of benefits that come with a salt-water pool, one of the biggest being that pool owners don’t need to buy, store, or handle chlorine. Instead, the system generates its own chlorine constantly (any time the equipment is running), saving time, hassle, and money. While there are plenty of benefits of chlorine generating systems, there are some potential problems that should be taken into account when considering a salt-water pool.
Salt water conducts electricity due to the electrolysis process. Any time you have different metals in a salt water pool, you essentially create a battery. Some amount of current flows between the metals. Don’t worry: the levels of electricity present are perfectly safe to swim in and will be undetected by swimmers. However, for the metals in your pool, it’s a different story. The electrons that make up the current are supplied by the metals in your swimming pool, starting with the weakest metal, which is forced to give up bits of itself in the form of metal ions into the pool water. This process is called galvanic corrosion, and it causes plaster discoloration and metal erosion. This type of corrosion can damage ladders, lights, and pool equipment–we’ve seen some pretty sad heater cores as a result. An electrical charge through the water pulls whatever is in the water out of solution, so electrolysis can also cause calcium to come out of solution and cause scaling on pool walls.
A zinc anode is a crucial part of any salt pool. The best option is one that gets plumbed into your equipment–this type of anode will best protect your pool and equipment from the negative effects of electrolysis. Another option, less expensive but less effective, is a disc-shaped zinc anode that sits in your skimmer basket. Zinc anodes are also called sacrificial anodes, because they corrode instead of the other metals in your pool. Zinc is a weak metal, so the anode sacrifices itself to galvanic corrosion so the other metals in your pool and equipment don’t have to. It also helps to prevent calcium scaling. This is an absolute must for a salt water pool!
I have a pool, that the hand rail coming out off the pool that is starting to rust do to electrolysis. I had a contractor in to do some work and cut the ground loop around the pool. he said he repaired it. I wonder if he did not repair it right, he is now saying its reverse polarity on the ground wire causing the electrolysis. can you point me in the right direction. thank you Bob
Can you test for electric current in a pool with or without a salt generator . I went through two heat exchangers in three years and it is not a chemical issue.thanks