Salt Water Sanitization
Here at the Spa Shoppe we get a lot of questions about salt water sanitization
systems. How do they work? Are they worth the expense? Do I need get new
equipment that can handle saltwater? Are they really chemical free?
For this post I thought I would go over what makes salt water different
from traditional sanitization systems, weigh out the pros and cons of
salt water systems, and dispel some common misconceptions about them.
How Does Salt Water Sanitization Work?
In a salt water sanitization system regular table salt (
sodium chloride), dissolved in water, is passed through a low voltage electric current.
This process is called electrolysis which energizes the salt molecule
and then combines it with hydrogen found in the water to form usable chlorine
sanitizers. As long as the system is running, and water is flowing past
the cell, it will continue to produce these chlorine sanitizers. The rate
at which it produces the chlorine is set by you, allowing you to turn
it up or down as outside temperatures , and usage, change over the season.
This same principle is also used in some hot tubs to produce bromine from
sodium bromide.
Benefits of Salt Water Systems
The first benefit of switching to salt water is the improved water quality.
This improvement is partly due to the salt itself, and also partly due
to the fact that you're not adding chlorine pucks. A "chlorine
puck" is generally less than 50% actual chlorine, the balance being
made up of stabilizers, binders, and other fillers. As these build up
in the pool, they can give the water a harsher, more "chemical"
feel to the water. By not needing to add any (or very few) chlorine pucks,
you avoid that build-up, and are left with more natural feeling water.
Salt water itself is also naturally "softer" feeling.
The other main benefit of switching to a salt water is the ease of maintenance.
Since they produce their own steady supply of chlorine, you do not need
to manually add chlorine in a salt water system, reducing the weekly upkeep,
while also avoiding having to handle chlorine. On top of that, if you
are away for several days or more you do not need to worry about your
pool becoming cloudy or green due to lack of chlorine. With all of that
said, you will still need to ensure the water is properly balanced, brush
the walls of the pool, and shock it periodically, typically every 2-4
weeks, to prevent any problems from arising.
Drawbacks of Salt Water Systems
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When shopping for a salt system, consider
buying a "low salt" unit to reduce the
potential for corrosion, and save on your
salt costs.
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The main downside of a salt water system is the potential for corrosion.
Salt water is more corrosive
than fresh water, the more salt present in the water, the more potential
for corrosion exists. To help combat this, many manufacturers have come
out with low salt units. Hayward, for instance, have introduced the AquaRite
Low Salt system which will effectively run at half the salt level that
standard systems require.
Another drawback of salt systems is their tendency to slowly raise the
pH of the water, which, if left untreated, can lead to scaling and water
clarity issues. This pH climb can be easily combated by periodically adding
a pH reducing chemical, usually once monthly. For more on pH and why it's
important to keep balanced
click here.
Some Misconceptions About Salt Water Systems
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Salt water systems are completely chlorine and bromine free.
As we've already seen that is not the case; they simply produce their
own supply of chlorine. They will typically also need to have some chlorine
added at the beginning of the season, and after heavy uses to maintain
a safe level of chlorine.
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All you do is add salt and it takes care of everything else.
Again we've seen that that is simply not the case. While it does eliminate
the need to manually add chlorine;
the water still needs to be balanced, shocked every few weeks, and salt
needs to be periodically added as water splashes out and is replaced by
freshwater.
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Salt systems will save you a ton of money on chemicals in the long run.
While it is true that you will save money by not having to buy nearly as
much chlorine, those savings are negated by the initial costs of buying
the system, and the cost of replacing the cell every 5-7 years. When looking
over the span of 10 or more years, the overall cost difference between
using traditional chlorine and salt water chlorination are minimal.
Proper Maintenance of a Salt System
So how do you properly maintain a salt water pool?
- The salt cell will not efficiently generate chlorine until the pool water
reaches a temperature of around 70 degrees Fahrenheit, so, for the first
few weeks a salt pool is opened, you will need to manually add chlorine
to prevent the pool from going cloudy or green. The amount of chlorine
should be minimal since cold water doesn't grow algae nearly as quickly
as warm water. A couple of chlorine pucks and some shock should be all you need,
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The cell should also be chemically cleaned at least once a season with
a special salt cell
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Clean your salt cell once a year to remove
mineral build-up that can greatly
lower your salt cell's efficiency.
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cleaner. Calcium and other minerals can build up on the cell through the
year, greatly reducing its efficiency. A layer of calcium buildup as thin
as a piece of paper can reduce the cell's ability to produce chlorine
by up to 50%. Cleaning the cell once a year will ensure that your cell
is always working at peak efficiency, and, since it will not have to work
as hard to maintain a chlorine residual, extend its lifespan.
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If you're having problems establishing a chlorine residual, you could
have an excessive amount
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Phosphate removers like Natural
Chemistry's Phosfree can help to
increase your salt cell's efficiency.
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of phosphates in the water. Phosphates are introduced to the pool when
organic materials, like leaves, enter the water. As phosphates levels
increase they can coat the salt cell, inhibiting its ability to produce
chlorine. If you think you might be having this issue ask for a phosphate
test next time you get your water tested. Based on that test, you will
add a phosphate remover, like Natural Chemistry's Phosfree.
- Most salt water systems come equipped with a super-chlorinate or "boost"
function. This is used periodically throughout the season, and after heavy
uses, to break up chloramines (used up chlorine responsible for red eyes
and the distinct "chlorine smell") and ensure that the water
stays clear. When activated, this function turns the cell up to 100% output
to rapidly build up the chlorine level and super-chlorinate (shock) the
pool. This works the cell harder than normal and can reduce its overall
life, while also increasing the chlorine level beyond what most people
find comfortable. To maximize the life of the cell, and keep the chlorine
level down, use a chlorine-free oxidizer to shock the pool instead of
this boost function.
- As previously mentioned, the cell will typically need to be replaced every
5-7 years.
- Lastly, salt systems can only do their jobs when there is flow past the
cell. Make sure that your pool pump is operating at least 12-16 hours
a day, during the day, to ensure that the cell has time to produce enough
chlorine to keep you water clean and clear.
When all is said and done, salt water systems do work, and work well,
but they are not the chemical free, no maintenance solution that some
people hope for. There are pros and cons to getting one installed, but
if you're willing to educate yourself on how to properly operate and
maintain the system, they can be a very convenient, and reliable, system.
If you have any more questions about salt water systems, or any other water
care issue, call our certified water care specialists at 905-666-5333.
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