Swimming Pool Blog
by Mark Garcia, July 24, 2017
Today's short post is a rant about people thinking that a Saltwater pool is somehow not a Chlorine pool. Pool buyers are often presented with two choices with a new pool, and somehow a saltwater pool has gained a reputation as a chlorine-free pool, but a salt water pool IS a chlorinated pool.
A saltwater pool is a pool with salt added, to around 3500 ppm salinity. The salt itself does nothing for sanitation, but when you run salty water through a small electrolysis machine (Salt Cell), chlorine is created inside the pipe, and released into the pool. Saltwater pools use equipment known as a chlorine generator, salt chlorinator, or salt system, all being the same.
A chlorine pool of course, is a pool that uses tablets or sticks to chlorinate the water, and granular or liquid chlorine for occasional shocking. Those with supplemental sanitizers like mineral purifiers (Nature2, Frog) or Ozonators can reduce their chlorine level by half.
Saltwater Pools use the Exact Same Chlorine
Saltwater systems make chlorine, the exact same chlorine that is released from pool chlorine products. In a saltwater pool, when H2O + NaOCl are run through the salt cell, the electric charge breaks apart molecules to create chlorine (Cl) and a few other byproducts, which are generally reabsorbed. The chlorine that is instantly created, hypochlorous acid, is the same exact chlorine that is released from chlorine tablets, liquid chlorine, or granular chlorine.
Saltwater Pools do have Benefits
- You can't taste the salt, but it can make the water feel softer
- Less storage and handling of hazardous chlorine products
- Breakpoint chlorination inside the cell reduces chloramines constantly
- Easily raise or lower chlorine levels, and view status on digital display
Saltwater Pools are not Maintenance Free Pools
- You still have to monitor the system, and test for salt, chlorine and stabilizer levels
- You still have to maintain good water balance; saltwater pool pH and Alkalinity rises rapidly
- Salt cells need cleaning to remove scale, although some systems do it automatically
- Salt cells last about 5 yrs; salt system parts like boards, sensors and switches may last longer
You may Still Need to Use Chlorine Products
- To raise chlorine level very fast for shock treatments
- To maintain chlorine level during pump, filter or salt system equipment problems
- To clear the water during opening or closing the pool, or for treating various water problems
Saltwater can attack Soft & Shiny Surfaces
- Galvanic corrosion can oxidize chrome surfaces in the pool, although sacrificial anodes can be used
- Salt residue can slowly corrode soft coping stones or stone decks, although sealers can be used
I'm not anti-saltwater pool, I'm just ranting about those (in the pool industry) that present the two as if they are two opposite approaches to pool care, when they are more alike than they are different. Saltwater systems are not better than chlorine pools, because they are chlorine pools!
Think of a saltwater pool as a chlorine pool - with an alternative chlorine delivery system.
Thanks for Reading!