Swg Or Ionizer

[macgd016]

Having experienced a problem with high CYA I am looking at alternative methods of maintaining a clean bright pool. I note that on this forum SWG seems to be favored but in Spain Ionizers seem to be very popular. This company in Spain www.sugar-valley.net/applications/index.php seem to have a multitude of products that together seem to automatically manage everything to do with water balance. I do not live at my house in Spain or I would probably just use liquid chlorine as this seems to be the simplest solution. Instead I have to rely on local 'expertise' which tends to be home grown and tends to be reactive rather than pro active which means that automated systems do have their attractions (and expense!) Does anyone have any views on the relative merits/drawbacks of SWG, Ionizers, algae and pH management and/or combining these as this company seems to have done.

[chem geek]

They are really apples and oranges since an ionizer system does not provide any oxidation of bather wastes and it only provides a backup of sanitation not nearly as powerful as with chlorine, though ionizers that have copper ions will prevent algae growth. You have to be careful, however, that the pH does not go up or else you can get metal stains, especially on plaster.

A saltwater chlorine generator (SWG) generates chlorine.

You have other options for handling the rise in CYA from continued use of Trichlor pucks/tabs. You can use a weekly algaecide (PolyQuat 60) or a phosphate remover, both at extra cost, to prevent algae growth even when the FC/CYA ratio gets too low. Another option is to switch to using unstabilized chlorine, usually chlorinating liquid or bleach (or Cal-Hypo if your Calcium Hardness is low, say in a vinyl pool), but you need to add these every day or two unless you have a pool cover. Another option is to dilute the water regularly, though that takes quite a lot of dilution to keep the CYA in check unless you backwash weekly (say, with a sand filter), have a smaller pool, and have rain overflow.

Richard

[Pool-newb]

..., and have rain overflow.

Richard

So unless your house in Spain is mainly on the plain ... (sorry, couldn't resist)

I also had huge problems with both CYA and stains. The CYA came from the previous owners using the 3" tablets with so much CYA, and the stains came from the previous owners also using the 3" tablets but also not maintaining the pH and causing a heater to rust out, which in turn deposited the metal on the pool walls.

In the meantime I've gotton rid of both but it has been a pain.

I currently use bleach to sanitize my water but I would never use any system that would introduce additional metals into the water. Everyone I've talked to feels that the salt water chlorine generator system is the way to go, and I know that I would immediately install one if I had a pool that I couldn't maintain every few days.

The site you mentioned does sell SWGs and there may be a bit of confusion. They refer to it as "salt electrolysis" but the function is the same; metal plates are put in the water flow and electricity is passed through the plates. A low level of salt (naCl) in the water reacts with the curring being passed through the plates and the salt is broken up into chlorine and other components. As the chlorine performs it's sanitizing work it is converted back into salt, and the cycle starts all over again.

[macgd016]

..., and have rain overflow.

Richard

So unless your house in Spain is mainly on the plain ... (sorry, couldn't resist)

Actually its in the mountains but that is another story. Thanks you both for your replys, I am fast coming to the view that I need to install a SWG but I'm concerned that doing so may necessitate running the pool pump for longer than I am doing currently. Try as I might I can't find any information on the length of circulation time needed to achieve a given 1ppm FC, or do SWG's work independently of the circulation. I can see that a SWG may just produce chlorine when its on and this will then be pumped into the pool when the pump is on but I'm not sure if they work this way or not.

If the above is a problem I could plumb an Intex Krystal Clear Chlorine generator into my Solar Heating system which has a separate low wattage pump. These systems are designed for above ground pools but are supposed to work with pools up to 20,000 gals. Given that they are inexpensive I suspect that they may not be up to the job though.

[chem geek]

You generally set an "on-time" for your SWG as a percentage so it will be on generating chlorine for that percentage of time when the pump is running. You should get an SWG that is somewhat oversized for the pool as that will last longer (not too much oversizing, though). So you may end up having the SWG be on 20-40% of the time, for example. You don't want it to need to be set to 80% or more since you don't have much room to go up higher when necessary.

You'll want to maintain a Free Chlorine (FC) level of at least 4.5% of the Cyanuric Acid (CYA) level. If the pool is exposed to direct sunlight, then usually the CYA level is kept high at around 70-80 ppm so the FC level should be around 4 ppm. See Water Balance for SWGs for more info.