After using ionization for many, many years, every since the Nature 2 came out (how many years is that??) (and then switching to the Floatron which is much cheaper in the long run) I can attest to how easily the pool can get metal stains when things get even slightly out of balance for more than short periods of time. Running the pool year round, at least 12 hours a day, usually more, with big pump, using commercial size Nature 2 cartridges, I had to change them out at least 3 times a year, usually more, at $100 plus per cartridge. Then there was the freezing of the vessels during especially cold weather even with water running through them. I had to replace at least three from freeze damage. Add in the cost of running pump so long and the money really mounts up. During this time I had virtually no algae when most others in this area were battling it. Yellow algae is a particular problem in the Texas area with sizzling summer temps and extremely high UV.
Then you add in the cost of powder for shocking. I went through at least 50 lbs a year for the weekly (sometimes more often) Spring/Summer/Fall shocking but, as I remember, the pool was probably frequently on the verge of an algae bloom when it got near time to shock again.
BUT...........
The main thing, though, was how safe was my water????? It would go from very high chlorine to none in the period of 4-8 days between shockings. On the high end, right after shocking, we were swimming in chlorine levels much, much higher than I would ever choose to swim in now that I'm going totally manually liquid chlorine (I don't have an auto chlorinator). Those high levels of chlorine for shocking really defeats the purpose of "low chlorine" sanitization, yes? Now, after learning my pool I can just go out daily and pour an estimated amount in with testing only every few days. Our loads are heavy (dogs, dust, sand, silt, much plant debris, birds) and pretty consistent.
I tried non-chlorine shocking for a while but it really didn't do the job.
And I haven't even mentioned the staining.......
I switched to BBB last summer and won't go back for any reason...... well unless chlorine becomes impossible to find, which is highly unlikely.
If someone insists on using ionization my advice for pool finish would be one that closely matches metal staining colors.
{EDIT} A little over a year after we moved here my swimming show dogs were getting bleached out coats from the chlorine and sun using the in-line chlorine tab feeder. Also, DH did not tolerate the chlorine and chlorine smell well so rarely swam. I switched to an in-line Bromine tab feeder. Although it is reported that Bromine cost more I remember that the costs were less, in the long run, because the Bromine lasted much longer tabs and less lost to UV. The bleaching of dog coats reduced singificantly and there was little Bromine odor. I switched to ionization as soon as I found out about it but I was, yet, another person who didn't realize all the disadvantages of ionization. Even after finding TFP, asking a lot of questions, and doing a lot of reading, I was still resistant to switching to BBB.
But for not too awfully long. I'm so glad I switched. BTW..... My puppies, two black Labradoodles and fawn Jake Mastiff (lots of different color highlights), who were in the pool hours during the day, with high UV, showed virtually no signs of coat bleach out last summer.
gg=alice
