Salt water pool chlorination?
I have the responsibility of two swimming pools and I thought I’d share some thoughts regarding salt water chlorination.
We took possession of our first pool in 1999: a 10×5 metre pool which had traditional treatment and was only 1 year old. I managed it without too much of a problem until 2007 when it had a black algae attack. This was dealt with but returned each year.
In 2011 we decided to have an Astral Sel 100 salt water chlorination system fitted to this pool, which cost about €1,150. This worked very well, in fact the chlorine production was very efficient, it completely eliminated any trace of black algae and we have never seen it again. The pool is now 14+ years old.
BUT: The control unit has recently gone wrong and has been examined by a local electronics expert and is unrepairable due to ingress of “a corrosive liquid”. The unit was installed professionally in a dry underground pump house, and was only 2.5 years old.
Installed 2003, 8×4 metre polyester insert supplied with a free Osec OS-3 self cleaning (South African) salt water system. This functioned well only until 2005, when the cell failed. The replacement cost around €400 including import taxes from South Africa. The cell failed again in April this year when I decided to abandon salt water chlorination in that pool. The cells were discarded, but the control unit was still working.
I have now placed the old Osec control unit from Pool 2 onto the Astral cells at Pool 1, and it seems to be working. When either the unit or cells fail, I will probably abandon salt water chlorination at Pool 1.
I used to be a supporter of salt water systems but now I’m moving away from that position.
Advantages of salt-water chlorination systems:
Easy maintenance and less maintenance when the system is working correctly.
No necessity to handle chlorine tablets or powder which are very unpleasant and toxic.
The salt-water is said to be better for people’s skin.
Less likelihood of a pool crisis through neglect, stays stable for longer.
Disadvantages of salt-water chlorination systems:
Very costly initial installation, and repairs when they are needed.
Short cell life, they are guaranteed for 2 years, but may last 3 years or up to 7 years if you are very lucky. Cell replacement is €400 – €500 if you do it yourself.
Extra electricity bills, as it is necessary to run the system for much longer per day, than a conventional pool, to maintain the chlorine levels.
I don’t think there is a clear winner in the salt-water/chlorine debate.
A salt-water system will probably pay for itself in 3-4 years, as no chlorine products should need to be purchased. Some salt will be required but it is very cheap to throw in a few 25 kg bags to top up the concentration.
Pool salt should be about 4 grams per litre (0.4%) so for an 8 x 4 metre pool with 40 cubic metres (40,000 litres of water) 160 kg of salt will be required initially, if converting the pool.
Want to know how to get rid of black algae?
Page reviewed on 6th Jan 2020