Why does this forum recommend FC higher than what is recommended on testing kits?

[Species 8472]

Typically, the test strip and cheaper chlorine tests recommend a range of 1 to 3 for all pools. In fact, anything above that point is considered high and out-of-range. Why do folks on this forum recommend a much higher level and in the 4 to 5 range for SWG pools?

 

[tim5055]

Because the industry recommendations of 1 to 3 fail to take into account the effects of CYA/Stabilizer on chlorine.

 

[kimkats]

Science. There has been a LOT to science put to use to find the levels used here. If you read the deeper end you will find all kinds to posts about the hows and why.

I do KNOW that the levels work! My pool has been clear since the day I put it up and added water due to TFP levels.

Kim

 

[Patrick_B]

It's also because of federal EPA regulations. They too fail and refuse to recognize Cya chlorine relationships, hence the suggested levels from all those in the industry.

 

[Richard320]

Because it works. Here's the scientific stuff Pool Water Chemistry

 

[chem geek]

See also the "Chlorine/CYA Relationship" section of the thread Certified Pool Operator (CPO) training -- What is not taught.

Because of FIFRA regulations the EPA enforces regarding pesticide product labeling, they will not allow any pesticide product to specify a higher dosed FC level than the 4 ppm that is the limit in EPA Drinking Water Contaminants standards. Nevertheless, commercial/public pools are regulated by state (and sometimes county) codes as with 5 ppm in New York (see 6.11(c)(1) and also note (4) which bans use of CYA), 8 ppm in Texas (see table on last page), and 10 ppm in Florida (see 64E-9.004(1)(d)(2)) that all exceed EPA limits.

The active chlorine (hypochlorous acid) level in pools at the recommended minimum FC for non-SWCG pools where the FC is roughly 7.5% of the CYA level is equivalent to a pool with only 0.06 ppm FC and no CYA. So comparing a pool with CYA to one without is like comparing apples and oranges. The way to look at it is that pools or spas with no CYA are usually hugely over-chlorinated because they have no CYA to moderate chlorine's strength. The effects are noticeable on swimsuits, skin, and hair.

 

[Species 8472]

Thanks for the information.