I hear the question at least twice a week …Hey Chris...“What should I use – chlorine Tablets or Salt water?” Not too many years ago, the question rarely came up, but now that Salt Chlorinators have matured into a more affordable technology, they are able to compete very well against the old industry standard – stabilized Chlorine Tablets.
Both methods have their advantages, and they are not mutually exclusive, that is – you can use a salt system, and still add tablets or granular pool shock if needed, if the pool pump or salt chlorinator is not working, or when opening the pool.
Let’s compare salt chlorinators with chlorine tablets, by evaluating between the two on the basis of Convenience, Cost, Effectiveness, Hazards and Maintenance.
Convenience
Chlorine Tablets - Can be purchased at most local hardware stores and home stores, so chlorine tablets are accessible and easy to get when needed. You can pay less of course, when you buy chlorine tablets online. When using chlorine tablets you can just put some in a floater and float them around the pool. The best way to dispense chemicals into your pool is chemical feeder, either an inline or offline feeder. This is as simple as putting tablets either 3” or 1” chlorine tablets into the feeder, adjust the dial to add the right amount of chlorine into the pool. Use a test kit to fine tine the setting.
When using chlorine tablets you need to also use something to shock your pool to remove bacteria and kill contaminants in the pool water. This should be done about every few weeks during the swimming season, or after a fun-filled day with lots of swimmers (heavy bather load). The most common types of pool shock are Calcium Hypochlorite, Sodium Hypochlorite (liquid bleach) Dichlor (stabilized), or Potassium Monopersulfate – a non-chlorine oxidizer.
When shocking your pool you must get your chlorine level up above breakpoint chlorination, which is usually around 10 ppm, but could be as high as 30 ppm, depending on the level of chloramines, contaminants or visible algae in the pool. Shocking the pool is very important for crystal clear water, and a safe swimming environment for your family and friends.
Salt Water Chlorinators – Salt Chlorinators disinfect pool water by producing chlorine from regular table salt (NaCl). This is done by putting 25lbs /1000 gallons, of pool salt directly into your swimming pool water. The chlorine generator produces chlorine from the salt through electrolysis. When the pump and filter are operating the water runs through the cell of the salt water chlorine generator creating the chlorine that sanitizes your swimming pool. Most new inground pool kits we sell are shipped with a salt chlorinator.
With a salt water chlorine generator, you eliminate buying chlorine tablets or pool shock, the salt system can be used to shock your pool. No more worry about storing the chlorine tablets because they are no longer needed. I have a chlorine generator on my own pool and my water is always sparkling clean and clear with very little maintenance. I do keep some pool shock on hand, just in case something breaks down, but so far, I’ve only used pool shock when I open the pool.
When using a salt water system the water seems much healthier to swim in; no burning eyes, no bleached hair or discolored bathing suits. The pool water feels much softer and silkier to your skin, and doesn’t dry out skin like chlorinated pools. Salt systems keep the water crystal clear and algae free and also makes your water chemistry easier to maintain because there is not as much fluctuation with pH or Alkalinity. Many people comment on the lack of chlorine smell or taste in my pool water too!
Conclusion: Salt chlorinators are more convenient and easier to use than chlorine tablets.
Cost
Taking a 20,000 gallon pool with a 6 month season, I compared the real costs of using a salt system, vs. using tablets, and they are surprisingly close. In the short term, under 5 years, tablets would figure much cheaper. But looking at the numbers long term, and a salt system may end up costing less than using tablets.
Our charts assume that the cost of chlorine will stay fairly stable, and that a new salt cell is installed every five years. At some point during 20 years, however, a replacement of the entire salt system (cell, sensors and controller) will likely be made, which would bring long term costs of salt systems and chlorine tablets closer together.
Conclusion: In general terms, and all things being equal, salt chlorinators and chlorine tablets should cost about the same, in the long run.
Effectiveness:
Chlorine tablets/shock and the salt water chlorine generators are both very effective ways to sanitize your swimming pool. When using the salt system you can eliminate buying and storing the pool shock so it is one less chemical you have to worry about.
There are different forms of chlorine and chlorine tablets. The most popular type of chlorine is the 3” or 1” tablet made from Trichlor–S-Triazinetrione, or Tri-Chlor. In regards to pool shock the most common granular shock is called Calcium Hypochlorite, or Cal-Hypo. Some pool owners prefer liquid shock, Sodium Hypochlorite, or Bleach.
When using a salt water chlorine generator you create chlorine from salt and it creates a hypochlorous acid. Th potent sanitizer is released into your swimming pool through the pool inlets to sanitize your swimming pool. With a salt system there is odor like normally associated with a typical chlorine pool and there also is no taste of salt.
Both salt systems and chlorine tablets are affected by water balance, temperature, sunlight and the amount of bather waste and organic contaminants it contends with. Cyanuric acid, or stabilizer is needed with both systems, to protect chlorine from the sun. Tablets and salt generators produce the same thing – hypochlorous acid.
In terms of efficiency of your time, using tablets and shock will probably take more time, although probably not by much.
Conclusion: Both systems are equally effective at controlling algae and bacteria, all things being equal.
Hazards:
When using chlorine, if you use a chlorine floater and the floater gets stuck in the pool behind the ladder or any obstruction than the chlorine could fade a pool liner or stain plaster if stuck on a step or if it tips over. Also if using chlorine make sure you don’t put the tablets into your skimmer or pump basket because this is very corrosive to the pool pump. Careful...!When dissolving pool shock always add shock-to-water, Not water to shock.
Always apply chemicals directly to the pool or water, and never allow sanitizers to touch other chemicals, get wet or become contaminated. When using a salt water chlorine generator you will have no odor and don’t have to worry about storing or handling chlorine.
Chlorine fumes can be a problem too – I had a customer with an inline chlorinator not producing chlorine. He took off the cover and inhaled chlorine gas fumes, fell backwards and hit his head on the filter!
When using a salt water chlorine generator, there is the concern of corrosion of the metals around the pool such as the steel walls, ladders, handrails, or lights. As long as the pool is grounded properly you should not have any problems with corrosion. I have a salt system on my own pool and I have no signs of any corrosion around my pool area, it looks as new as it did on day one. They do have an anode that you can clamp on your pool ladder or one you can put in the skimmer basket and this will eliminate any chance of possible corrosion.
Conclusion: Salt is safer. Transporting, storing and handling chlorinated products is definitely more hazardous than using a salt system.
Maintenance:
When it comes to maintenance for a salt water chlorine generator you should clean the salt cell at the end of the season by using a 10 to 1 ratio of muriatic acid and water. Most of the salt water systems have self-cleaning cells so you should not see too many calcium deposits on the electrolytic cell of the chlorine generator.Eventually, the salt cell will fail, and will cost 30-50% of the cost of the initial unit to replace, but is something that you can do yourself.
During the course of the season you might need to add a little more salt if you lose a lot of water due to evaporation or splash out. Also check the stabilizer level in your pool, and add more once or twice per year, salt systems use more than pools using tablets, which have stabilizer already in the tablet.
For chlorinators, they can go for years without repair or maintenance, and repairs are small and inexpensive. Tablet feeders usually have much fewer maintenance concerns and issues.
Conclusion: Salt systems require a bit more maintenance, and repair costs can be much more expensive.
Top
In reading the information above you can tell my personal prejudice, and where my preference lies. I love my salt generator, and would never go back to tablets. I like the benefits of using a salt water chlorine generator and find it easier to maintain a swimming pool.
Right now, in America, I would estimate that about 1/3 of pools are salt, and the rest are using tablets or liquid chlorine. Salt systems are gaining ground, however and I would predict that in 5-10 years, the number of pool owners using salt will have risen to over 1/2!
Stay-Tuned!
Chris Low
SPP Pool Expert