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deleterious effect of trichlor

Posted by dalehileman ( on
Fri, Sep 17, 10 at 12:14

Trichlor tabs are handy, requiring attention/replacement only once or twice a week but criticized for their supposed cumulative effect upon CYA, presumably requiring progressively higher levels of FC to the same effect. After 13 years using tricolor tabs in the same water however (except of course for that replacing evaporation) according to a sample conducted to our friendly local Bills Pool & Spa our CYA level was still in the "normal" range

(Don't emulate our example, however, as 13 years is too long. We did, however, finally replace most of it not only to drop the CYA but for other reasons as well)

In the first place, contrary to pronouncements by board forum "experts" the mutual effect of these two values is still highly controversial, leading one to wonder (1) how long it must take for CYA to reach "excessive" levels, (2) if the increasing requirement for FC is really valid

Follow-Up Postings:

RE: deleterious effect of trichlor

For the most part I agree with you. Especially if the pool has a backwash system. To where the consumer will backwash and replace with fresh water this will in most cases counter the build up of CYA. But this will not work on a cartridge system where in most cases the water that comes out of the pool is evaporated water only leaving behind the CYA so over time allowing a build up of CYA. In addition to the buildup of CYA. If the consumer uses alot of Cal-Hypo shock. You also run the risk of building up calcium levels as well. This all being said I agree there is and always will be a debate over the CYA levels in reference FC in the pool. There are also as I have stated many variables that dictate the build up of CYA in pools. Even more than the ones stated here.



RE: deleterious effect of trichlor

Yet if one persistently pursues a controversial topic on certain of the pool forums contrary to the pronouncements of "experts" therein, he is in danger of being banned

Still in my case after 13 years accumulation it's hard to understand why the CYA remained in "normal" range

RE: deleterious effect of trichlor

I got the same reaction when I went on that forum as well. It almost came across to me as some were the ultimate in pool knowledge where as I found some of the information lacking in expertise but more personal opinion than acual fact. I am glad to see I am not the only one who got the same welcome.

RE: deleterious effect of trichlor

There are several ways to lose CYA. Backwashing, spash out, pool closing, pool leaks and some have reported bacteria lowering CYA as well. Also, many have reported a drop in CYA with closed pools over the winter not only because they drain some of the water out of the pool but also because of the chemical reactions that can occur in a dormant pool. Many pool owners can successfully operate a trichlor pool because they either backwash a lot and/or close the pool every year. A pool with a sand filter that is open only 3 months out of the year should be able to operate a trichlor pool without any problems at all. But that still doesn't mean you should ignore CYA.

Also, I frequent many different forums and I don't think any of them have ever said it was impossible to successfully operate a trichlor pool only that it can cause problems IF the CYA levels get too high. And there are plenty of examples of pool owners ignoring CYA and having to battle algae blooms so it is not an unfounded premiss. Plus the chemistry supports the theory that CYA binds to chlorine so it cannot do useful work therefore, the more CYA you have the higher the CL level has to be.

I think the most important thing is to understand the consequences of operating a trichlor pool not that it is impossible.

RE: deleterious effect of trichlor

Irish thank you for the support. I was beginning to feel quite alone in my skepticism. I've encountered the "Netiquette Nazi" in other sorts of forums as they seem to be drawn to Internet boards possibly as a subconscious compensation for a felt lack of power in everyday life

For that reason they seem especially drawn to "Admin" positions

Mas thank you most kindly for all that background on CYA. It would be interesting to learn what sorts of chemical reactions that can occur in a dormant pool tend to lower it, as such if harmless to the swimmer might be investigated as means--surely less expensive by far than replacing most of the water

Also interesting to note you cite the CYA-FC connection as a theory because if you should question it at some sites you'd be fiercely attacked

RE: deleterious effect of trichlor


Why does the GW algorithm linkify "boards"

And Admin, forgive me, but f you're listening, have you yet learned what happened to the missing "Edit" link"

Thanks all

RE: deleterious effect of trichlor

If you are really interested in learning about pool chemistry, the sites I would recommend are both the and While they are fairly pro BBB and do not think well of Trichlor, there is still a lot you could learn from both sites. Also, I think you know Chemgeek from other forums and he has a very good handle on the chemistry behind the CYA and Chlorine relationship so you might want to readup on some of his post, see below.

Here is a link that might be useful: Pool Water Chemistry

RE: deleterious effect of trichlor

Thanks mas and yes geek is surely one of the most helpful and indulgent. But frankly I'm overwhelmed by pool chemistry but thanking you and him for any and all simplification you can offer

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