Chlorine generator for pool/spa treatment

[henerythe8th]

I will be buying a house that comes with a hot tub soon. A co-worker mentioned a chlorine generator type treatment system (I previously had no idea that one existed). I looked these systems up on the internet and there are several available commercially, but are quite spendy. I was wondering what would be necessary to put one together myself...
Essentially, you add table sale NaCl to the water to the point that it is "nearly salty". The Cl is separated from the Na via an electrical current (anode/cathode), the chlorine is now free to "kill" the bacteria, etc. and when done is re-attached to the previously freed Na. A very basic eplanation, but that's, essentially, the description from one of the pages that I looked at.

Any ideas?

 

[kenvlach]

You are talking about systems that electolytically produce a dilute ~0.8% sodium hypochlorite NaOCl solution. You should find more sources if you search for "hypochlorite generation."
These are also sold for wastewater treatment in the metal finishing industry. The advantage is that you don't have drum or bulk storage of the more concentrated commercial NaOCl solution inside secondary containment.

Re your idea of building such a unit yourself: you either can use highly inert electrodes, such as titanium and coated titanium, see

http://www.severntrentservices.com/...infection_products/hypochlorite/ct_series.jsp

or else use less expensive material & replace as necessary. It is probably undesirable to add Al, Cu or Fe to your solution, and titanium is rather expensive in small quantities, so I suggest trying 316 SS sheet for D-I-Y.

As you would also need a power supply (essentially a transformer & rectifier), I don't see how such a system could pay for itself vs. buying liquid or granular bleach, NaOCl or Ca(HOCl)[sub]2[/sub], respectively.
[might help if you are seaside & have a saltwater pool]

 

[EngrInfo]

You are talking about a salt-water pool using a salt-water chlorinator. These system typically require the addition of salt to the pool or spa to where the salt residual is somewhere around 1500 to 2500 mg/l depending on the manufacturer.

If you want to make your own chlorine generator check out

http://www.chlorine-generator.com

for more information.