pool store recommendations and high CYA??


Active member
Nov 4, 2007
Chattanooga TN
I've been reading through alot of the posts about CYA and it seems that the pool stores are recommending shocking and using their chlorine pucks and in the long run all it does is raise the CYA resulting in a harder time maintaining chlorine levels. I just restarted my pool and following PB suggestions (I've shocked twice, but I have NOT kept a puck in the skimmer at all times like they told me to) my CYA is already at 60 and before (1st go around with PB and doing what they told me) my CYA ended up at 150+. Is this a way to keep you coming in for more chemicals or do they not realize what they are telling you to do?? :?:


Mod Squad
TFP Expert
Apr 4, 2007
SW Indiana
I think most of them don't know any better. Some people get by fine because they change enough water every year to keep it under control.

chem geek

LifeTime Supporter
TFP Expert
Mar 28, 2007
San Rafael, CA USA
I think it's a combination of a lack of education of pool store personnel combined with the manufacturers of stabilized chlorine products (Trichlor and Dichlor) promoting a mantra of "CYA doesn't matter; only FC levels matter" in order to sell more product along with an understanding that it is more likely for a pool to get algae at higher CYA levels and therefore more likely to require the use of algaecide and related products. Also, there is subtlety with products such as Trichlor since they first appear to be inexpensive sources of chlorine, but when you factor in the pH Up products that are also required, they are actually more costly (see this post for details).

The "guaranteed algae free" programs that combine Trichlor with algaecide do work, but the manufacturers don't say that chlorine alone can keep away algae of you keep the CYA levels in check and watch the FC/CYA ratio. So it's not lying, but just offering a proposal that works and is profitable.

However, all of the above analysis is probably not what pool store people go through. They pretty much learn from the industry while the trade groups (e.g. APSP) more or less are run by the manufacturers (Chemtura, makers of BioGuard/SpaGuard products, was a primary funding member of APSP when it resurrected from NSPI, but this is less visible now).



LifeTime Supporter
Platinum Supporter
TFP Expert
May 7, 2007
Silver Spring, MD
There is some basis to their recommendations. Many pool owners won't follow directions if they are even slightly complicated. Keeping a trichlor tablet in the skimmer or several in the tablet dispenser is about as easy as it gets. Shocking regularly solves problems if you frequently allow chlorine to go to zero. And in the top half of the country with a sand or DE filter, regular backwashing, and conditions that cause CYA to disappear over the winter, it is possible to run a pool with trichlor.

If you are willing to put in just a little bit of time, there are *far* better approaches. But for people who pay only marginal attention to their pool it is difficult to come up with something that works at all. Trichlor "works at all" in those marginal situations. It doesn't work well, nothing will, but it kind of works. About the only other thing that would even kind of work in those situations is a SWG.