Somehow most people gawk when they first hear about a residential salt water pool. I suspect it reminds them of the salty feeling of ocean water and the resulting itchiness once it dries out. It never really affected me, so I don’t get that visceral feel. The reality of salt water pool is actually quite far from what you experience in sea or ocean water. The salt concentration needed to run a salt water pool is an order of magnitude lower than of sea water and hardly detectable by humans. Salt water pool have been in use for a long time and in Australia, 90% of the pool are run that way. It’s a great way to solve the problem of pool water sanitation.
The need for water sanitation
The main advantage of a salt water pool, is that the salt can be used for water sanitation. Water sanitation is a big problem for residential pool (I can’t even imagine what it must be like for commercial pools). The most common form of sanitation is based on the addition of chlorine into the pool water, mostly in the form of stabilized chlorine tablets. The goal is to maintain a 1-1.5 ppm concentration of free chlorine (Hypochlorous Acid) in the water to reduce the level of micro-organism and keep the water clean. Unfortunately, the free chlorine reaction with ammonia wastes from the bathers creates a by product called Chloramines (or combine chlorine), causing the typical chlorine odor that people associate with heavily used pools. It also is responsible for red eyes and irritates the skin.
Your own chlorine factory
Through the process of electrolysis, water passing over the chlorine generator cell produces chlorine that is instantaneously transformed into Hypochlorous Acid. The water passing thru the electrolysis cell is hyper chlorinated and sanitized.
What about the taste?
Ocean water has a salt content of around 35,000 parts per million (”ppm”). Humans have a salt taste threshold of around 3,500 ppm. Most chlorine generators require a salt content of 2,500 - 6,000 ppm in the pool. A unit that needs less than 3,500 ppm to operate effectively is optimal.
Swimming in a mild saline solution is much like taking a shower in soft water. Generally, when people swim in a non-chlorine generator pool (a pool with no salt water in it) they feel like their skin dries quicker upon exiting the pool. They may feel and/or see a whitish residual, chlorine flaking, on the skin. In a salt-water pool (one with a chlorine generator) the water feels smooth, your skin feels smooth and many people feel more refreshed.
In practice
When looking for a salt water chlorine generated, I decided on the PoolPilot Digital from AutoPilot System. It operates at 3,000 ppm salt and has a very high rate of chlorine output, plus I liked the digital display for a high tech touch.
I have been running this system in a newly re-plastered pool for over a month. I’ve been surprised by a constant high PH. After some research, it appears that a new plaster will take quite sometime to cure (up to a year) and will force the PH to constantly drift upwards in the process. Additionally, it looks like salt water generators tend to raise the PH as well. For now, I’m planning to add about 1Gal of Muriatic Acid every week and monitor the results.
I’ve yet to enjoy the pool because of other backyard work going on. Will post my results once things settle a bit. Stay tuned.
2 Comments
You will love your SW pool. Your skin feels great, it’s like swimming in soft water
Any reported problems such as cloudy water when using silver based anti-microbial products in a salt water pool? Silver can combine with chlorine producing the precipitate silver chloride.