Tuesday, January 24, 2012
K.I.S.S. - Keep It Salt for Safety
You might think that manufacturing your own chlorine at home would be dangerous and unwise. You might think that adding chemicals to your pool is also dangerous and unhealthy. Both of those statements are false.
The manufacture of liquid bleach (chlorine) by using salt and a small current of electricity was started in the 1800’s. Now we can do this safely right at and in our pools and spas.
As chlorine works by oxidation which is the ability for a molecule to grab and burn oxygen we must use chemicals that promote this reaction to rid our pool/spa water of waste and bacteria. This would require the oxidizer used to be unstable so it can react quickly. We see this in fire situations where we are told not to open a door where there is a fire. Increased oxygen flow increases the ability to burn and flame. An oxidizer has the ability to burn, combust and explode depending on how fast it reacts with another chemical or product. This makes storage of oxidizers or shock products such as calcium hypochlorite and sodium hypochlorite dangerous to store in your home or business. You may be required to post a warning or informational card on your home, business or vehicle when transporting. We know that adding water TO calcium hypochlorite can cause an explosion. If a fireman comes to your home and business and sees a pool in the backyard they are wondering where you store your chemicals for they do not want to put a stream of water on a container of this strong oxidizer and create a worse situation.
The storage and handling of chlorine is also a problem that could be costly and dangerous. The fumes are very corrosive and if product is stored near lawnmowers, chain saws, chemical controllers, pumps and other usually stored items damage will occur in a short period of time. Unopened containers of chlorine can become brittle and crack allowing product to come in contact with grease or oils and ignite. Fumes are also dangerous to breathe and precautions for breathing and eyes must be taken when opening and dispensing.
Chlorine generators have no storage of dangerous products. The main product used is salt and there is no need to store any. Even if you did store salt it is not dangerous. It’s not expensive either.
With manufacturing the chlorine yourself the costs come down dramatically for sanitizer. The salt only needs to be replenished when the chloride (salt) level gets low due to splash out, leaks, backwash or dilution of the pool water. The salt stays in the pool during evaporation but can leave on swimmers and any way the water is physically removed. With rising costs of inorganic chlorine salt generation is economical and all of the initial costs can be recouped in a short period of time.
A disadvantage would be the initial cost of the unit and installation. The initial costs are much higher than an erosion feeder and it seems odd to be adding hundreds of pounds of heavy salt bags to your pool initially.
What is convenient is that to super oxidize the pool as needed you can just turn the production up on the unit or use a non-chlorine (MPS) type shock. There is no mixing of chemicals, fumes or work involved other than testing the water regularly to keep pH in correct levels.
It is still a chlorine pool so our water chemistry practice is still the same. Keep the chlorine level at 1.5 ppm to 3ppm and balance the water within parameters. However we do keep the total alkalinity at 80 ppm to 100 ppm to help us keep the pH at an acceptable level.
The mineral salts make the water feel soft and luxurious. It has the “ahhh” effect on people. Saline solutions are used for contacts so you know that the salt in the pool will not burn your eyes or delicate parts.
The pool does not taste like salt as it is not over 30,000 ppm such as seawater. But it does not have a steel taste either that can be found in pools with low pH and alkalinity levels. Pool water likes to be balanced and go to a pH of 8. However a pH of 8 is not acceptable in a chlorine pool as the weak chlorine (OCL) becomes more bountiful. Therefore we need to be sure as we do in all chlorine pools to keep the pH in range of 7.4 - 7.6.
Due to the electron process the cells can scale up so there is a need to acid wash the cell periodically.
As the pool is higher in total dissolved solids from the minerals of the salt it is more conductive to electron flow. This can cause some corrosion in a pool that is not properly bonded. However a inexpensive zinc anode can be placed in the skimmer basket to help counteract the process.
With producing chlorine on site the pool water keeps a steady residual as it is not depending on a feeder (human or automated). With less chances for a low sanitizer event then it is less likely that algae, biofilm or bacteria are allowed to grow. Evidence is suggesting that many oxidants can be formed within the water and further decrease biofilms. It is imperative to keep chemicals in the pool to combat bacteria, biofilm and other pathogens as they are more dangerous than the recommended chemicals.
There are three available models of chlorine generators: brine, in-line, and in-pool. I prefer the in-line model due to it’s convenience and available options. The in-line model is comprised of a cell with housing cord and power supply. Some models have a temperature probe that can increase and decrease the chlorine production automatically. Some models will read the actual salt reading in the pool where as some read an average of the past 30 days. It is important to know which type you have to avoid problems. Some in-line models will stop producing chlorine when the salt level is too high or the water temperature is above 96 degrees. This disadvantage does not have to be as long as you know what to expect.
The in-pool units can be a nuisance as kids may want to play with them. Brine tanks have to be monitored carefully as the by product of caustic soda has to either be drained or introduced into the pool.
As with all equipment there can be a failure and a resulting down time. It would be recommended to keep a back up method of sanitation for times as this.
Salt systems are not new to the pool industry. However they are more user friendly than ever before. You do not need to be a chemist but you need to have a good pool professional to check your water periodically or have a good understanding of water balance and recommendations for salt water pools.
Less work is a nice by product of the safety issues that present themselves when using a chlorine generated pool. The safer the pool and safer the water provides a safer environment bathers and community.