Downsides to salt pools

[chem geek]

Gunslinger,

You may be right, but users of this forum, including Evan (waterbear) noticed that the output efficiency of the salt cell fell dramatically at lower CYA levels. That is, you needed to increase the time and/or power of the salt cell to achieve the same FC level when the CYA was below the 70-80 recommended range and this effect was MUCH larger than the sunlight protection effect of the additional CYA (which is quite minimal at higher CYA -- see this graph) . Now this specific CYA level probably varies by manufacturer, but this effect is absolutely real as it was reported by multiple users. Maybe your salt cell is one of the lucky ones that operates well at lower CYA, or maybe you never got to the 80 ppm CYA where the efficiency dramatically improves for some salt cells.

So at least some SWG manufacturers may be recommending higher CYA in order to have higher efficiency. The issue then becomes whether efficiency of chlorine generation is the only factor or whether the proportion of oxygen generation is also affected. I don't know the answer to that and was just speculating based on chemistry -- we don't have real-world data on SWG output (i.e. measuring the gasses) to know for certain.

giroup01,

I believe the high CYA recommendation is primarily for SWG cell efficiency as mentioned above. I do not know if the oxygen effect is real (there might be coatings on the plates to inhibit oxygen generation, if that's even possible) or if the manufacturers know about it if it is or if they recommend higher CYA partly for that reason. Basically, I don't know a lot. But if the chlorine generation rate goes down at lower CYA but the conductivity stays the same and there is the alternate reaction of generating oxygen available, then it seems reasonable to assume that more oxygen is generated at lower CYA. The extreme example of this occurs if you remove all of the chloride and just have a different electrolyte (sulfates, carbonates, etc.) in which case you get pretty much ONLY oxygen and hydrogen. I had fun as a kid making such concoctions and carefully exploding them (this is definitely a "don't try this at home" scenario where you must not use glassware and should wear glasses).

Richard