Salt Swimming Pools are Gaining Popularity in Canada

Canadian Spa & Pool Magazine Volume 2 Number 1

 

You have heard about them and if the rumors are true, this could be the biggest thing to hit the Canadian pool market since the heater. There seems to be no end to the talk about how great these things are but what is the real story? Salt chlorination is gathering momentum as the way to go in pool sanitation. Is it really that much better? The stories of chemical free and no more pool maintenance sound great but nothing is ever as good as it seems. Or is it?

We as Canadians think that salt chlorination is a new idea. The reality is that it has been around for many years. The Australians are the ones that first made salt chlorination functional and reliable. Watermaid founder Ted Romer started working on the idea in the 1960’s and perfected it by the early 70’s. The idea of producing chlorine from a salt solution had been around for so many years, that a patent of the idea was out of the question. This left the door open to several other manufacturers who realized the market potential of these devices and started producing them a few years later. Today a quick search of the Internet will show that there are a number of different models available. That same search will dig up a lot of stories about how great the systems are and, like a lot of things on the internet, you need to be very skeptical of the things that are claimed. In this article, we will touch on some of the myths and realities of salt chlorination and try to make your decision about buying a salt chlorination system, a little easier.

To help understand the realities of a salt system, we need to have a basic understanding of how they work.

First of all, there is no magical way to create a salt pool. It is as simple as adding salt (and a quite a bit I might add) to your pool. Here comes the first myth of salt pools.

“You need to add special salt to your pool.”

You can buy “special” salt if you want to but the truth is, salt is salt, you can buy expensive stuff in pretty packages or you can stop by the hardware store and get some good clean (and cheap) water softener salt. You take it home and dump it in your pool. We have some very clean salt deposits in Goderich Ontario that are producing some cheap and clean water softener salt. If you can get your hands on sea salt, that is another good way to go but keep in mind that all we want is salt and we shouldn’t be spending a lot of money on it. Whatever one is cheaper; as long as it is clean and doesn’t have additives, use it.

When the salt dissolves, you will have a salt pool. If you left it, it would grow some of the nicest algae and bacteria colonies that you could ever imagine. What we need to understand is that it isn’t the salt that kills the creepy scummy stuff in the pool, it is what we do with the salt that makes all of the nasties go away.

A salt chlorinator consists of a power pack and a cell. The cell is always located in the plumbing after the pump, heater and other equipment. The cell is simply made up of a cathode and an anode, which is powered by the (you guessed it) power pack. There are different ways of arranging the anode and cathode, and manufacturers have patented the way that their cells are made or controlled. For the sake of simplicity, let’s just stick to the idea that all cells have an anode and a cathode. When current passes between the cathode and the anode, it splits the salt molecule, which is in the water. When the salt, which is sodium chloride, splits, it frees up a sodium atom and a chlorine atom. At the same time hydrogen and oxygen are being freed from the water (H2O). Now before I ramble on too long and you roll your eyes and move on to something else, let me simply say that the cell produces sodium hypochlorite from this splitting of molecules. Sodium hypochlorite is the same stuff that you buy in the jugs at the pool shop. We just make it ourselves on site. Like most things home made, there are no additives which the chemical companies put into the jugs of chlorine to keep them from going funky before you get them home. This is where the next myth comes in. In fact it is probably the biggest one out there.

“Salt chlorination systems are chemical free.”

The truth is salt systems produce a chemical compound, which is necessary to sanitize your pool. In fact it produces one of only 2 chemicals that are recognized by Health Canada as a way to safely sanitize a swimming pool. Those are chlorine compounds and bromine compounds. Some salt systems can even generate bromine but I’ll leave that for another article.

Before we leave the thought of salt systems not being chemical free, it would probably be good to understand where this myth comes from.

First of all, chlorine generated on site by a salt chlorinator does not need chemical stabilizers and other chemicals that manufacturers of bottled and granular chlorine need to add to their packages. These additives tend to drive the pool Ph and total alkalinity off as well. When this happens, chemicals are required to bring the Ph and total alkalinity back in line. With a salt chlorinator, the pool solution is balanced and since you generate the sanitizer from that balanced solution, the pool Ph and total alkalinity tend to remain constant. The only things that can drive the pool balance off are the things that jump, or fall into the pool.

So can a salt chlorination company claim that their chlorination system is a chemical free way to sanitize your pool? Of course not! Can they claim to drastically reduce the chemicals required to maintain your pool? I guess we would have to give them that one.

The last little bit of chemistry that I will force onto you is the salt itself. A common question is, “How much salt will I need to add to the pool in a season?”

The answer is; how much splashing will be allowed in the pool?

The salt is not consumed in a salt pool. When the salt is split to form the sanitizer for your pool, the “chlorine” which is generated, attaches to the gross stuff in your pool. If it can’t find anything bad to attack, it will recombine with the free sodium in the pool solution and become a salt molecule again. If it does jump on some bad guy in the pool, it will hold him until it goes back through the cell of the chlorinator where high concentrations of generated chlorine will oxidize the bad guy and free up the chlorine again. This is another advantage of a salt chlorination system. There is a constant generation of sanitizer and a constant super chlorination effect within the cell, which prevents a buildup of combined chlorine in the pool. This combined chlorine (mono, bi and tri-chloramines) is what gives a dirty pool its characteristic strong chlorine smell and it is also what makes peoples skin itchy and red and contributes to burning eyes. These complaints are typically non-existent in a salt pool.

The only time that you will need to add salt to your pool is after you have backwashed a few times, when you fill the pool in the spring or when you and the kids have splashed a lot of water out of the pool. Salt is not lost due to evaporation. It is left in the pool.

So if a salt chlorinator generates chlorine, why is everyone raving about them? The answer is, convenience, economy and the feel.

Convenience: You don’t have to dump chlorine in your pool. This is a great thing for people who have pools at the cottage or summer home. It is also nice to be able to go on holidays for a week or two and not return to a green slimy mess.

Economy: On average, it costs about $400.00 per year for chemicals for your pool. Some spend more, some a little less, but the average is around $400.00. Most good quality chlorinators will pretty much pay for themselves within the warranty period offered.

Feel: This is the one that is the hardest to explain. When we first heard about salt pools, most of us thought about swimming in the ocean and that sticky feeling we got when the seawater dried on our skin. The salt levels used in salt pools are a lot less than that found in seawater. Ocean water is around 35,000 parts per million salt. Salt levels in salt swimming pools are between 3,000 and 6,000 parts per million depending on the brand that you choose. Some units are damaged by higher salt levels while others are designed to operate at higher levels without voiding the warranty.

The next question is, how does this make the water feel more comfortable?

Well, you asked for it; our body chemistry has a salt level of 9,000 parts per million salt. If you remember your high school biology, you may recall osmosis and how solutions try to balance themselves across cell membranes. If you weren’t paying attention that day, it can be summed up simply (yes I know that it is a little more complex than this) by saying that a salt solution will try to balance itself. If we jump in the ocean, the salt concentration in the ocean water is 35,000 parts per million. The salt concentration in our body is 9,000 parts per million. For simplicity sake, lets say that the salt is prevented from moving through the wall of the cells in your body but water can move. Think of it like a screen door in the summer time. The nice breeze can move through but the bugs are too big to get through. So here we are standing in the ocean wondering what is happening. Well, the solution in your body is trying to balance with the solution in the ocean and it wont stop until they are in balance. The salt can’t move but the water can, so the water in our body moves into the ocean water to try to get our body’s salt solution to 35,000 parts per million. Most of the time we don’t even notice this dehydration of our bodies.

Now if we take a salt solution that is close to our body’s salt level, there will be very little movement of fluids between the pool and our bodies. A regular pool has very little salt so the water is forced into our bodies causing the well known wrinkling of our fingers and toes. It is also another reason for the discomfort of our eyes when we open them in a regular pool. With a salt pool, there is little to no fluid transfer so the water feels more comfortable and our eyes don’t sting. Salt also has a natural softening effect on water, which makes the pool feel even better.

There are a number of options available on salt chlorinators today. Some have salt level indication, some have ph indicators, digital displays and pc links. Other have stayed away from complicated systems and sensors to improve unit life and reliability. For the pool owner, you need to decide what you really want and need on your system. With complicated systems, there is often a trade of in warranty but then again, you may think that those extra toys on the chlorinator are exactly what you need. The best advice is to shop around and understand the advantages and disadvantages of the units available.

• What is the chlorine production rate
• What salt level do I plan to use in my pool
• What unit will work at that salt level
• How hard is it to clean
• What kind of product support is available

Mark Manning
President
Watermaid of Canada Inc

www.watermaid.ca
mark@watermaid.ca
1-877-987-6243