Safe free chlorine levels???

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Dawnpj

Dawnpj

Member
Aug 2, 2019
11
Hawaii
I would appreciate help in trying to understand/figure out this cya/FC levels. We bought a home recently with an above ground 6000 gallon Polygroup Summer Waves vinyl pool. The filter/pump is attached to the side of the pool with the inlet at the same level as the return at approximately water level. The filter is a cartridge A or C purchased locally.
So after all of that, I just went through a bout of combating cloudy water. After finding this site, I stopped using the stabilized tablets and switched to household bleach. I purchased a “strip” test that would give me a ball park of my CYA level: it’s somewhere around 70 ish. With the CYA/FC chart I need to keep my FC around a 6. My water is clear, but my concern is the safety of swimming in a pool with chlorine at that level. I realize that doing a partial water exchange is needed to bring the CYA down, but need to plan for that and would like to know about the safety of running the higher levels until the exchange can happen. Thank you in advance for the help.
 
It is perfectly safe to swim up to the SLAM level FC listed for your CYA. That is still less active chlorine (hardness) than an indoor pool with 0 CYA and 1ppm of FC.

The old 1-4ppm recommendations from the EPA are for drinking water, not pool water that has CYA in it. The FC/CYA relationship had been ignored by the pool industry since the 70s, but slowly they are starting to accept it and update their recommendations.

If you want to dig in:

Pool Water Chemistry

This thread presents my findings so far on pool water chemistry including the following: More Accurate Calcite Saturation Index (CSI) to replace Langelier Saturation Index (LSI) Calculation of ppm HOCl (disinfecting chlorine) at various levels of Total Free Chlorine (FC) and Cyanuric Acid (CYA)...
www.troublefreepool.com www.troublefreepool.com
 
Aloha and welcome to TFP! :wave: Also keep in mind that test strips are a horrible judge of CYA and provide less than marginal results or accuracy. You really need to use a TF-100 (or Taylor K-2006C). See Test Kits Compared. Nice to have you with us.
 
Welcome to TGP!
What TexasSplash said. I used test strips when we started. Thought it was really cool, take a picture with phone, keeps a log for everything.
Then I left phone in house, read strip by comparing to the bottle. Totally different answers than I was expecting.

Long story short. Found TFP, got proper test kit, drain half the pool, now sparkling water, no algae outbreak in a year.

Testing is really not that hard and tons of support here if you have issues.
 
Unfortunately the CYA on the strips is one of the most inaccurate. If you've been using tablets and granular shock products, you absolutely do have CYA but unless you know exactly what you've added from a 0 CYA level, you won't be able to guess any better than the guess strips.

I wouldn't disregard completely the 70 that the strips show, but know that it might be much higher if all you've ever used is stabilized chlorine.

Now, to sort out your test kit purchase. Maybe someone can chime in about how long it takes to ship a TF-100 to HI. It came in <4 days to the west coast, so that's fairly fast. But add on another leg across the ocean, maybe not as fast as you'd prefer. Therefore, if Amazon Prime works as well as it does on the mainland you may be quicker served by a K-2006c.
 
Note that you have no idea on the freshness of the reagents when ordering from Amazon. TF-100 always comes with fresh reagents that should last 2 years or more if stored well.
 
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ajw22 said:
Note that you have no idea on the freshness of the reagents when ordering from Amazon. TF-100 always comes with fresh reagents that should last 2 years or more if stored well.
Click to expand...
I bought Taylor R-0013 and R-0871 on Amazon. Are you sayingI can't trust the Best y" date tht is stamped on the bottle? Says it is best by 7/2020.
 
CincyDools said:
I bought Taylor R-0013 and R-0871 on Amazon. Are you sayingI can't trust the Best y" date tht is stamped on the bottle? Says it is best by 7/2020.
Click to expand...

You are good. Some folks have bought online and got best by dates in a few months from when they received it.
 
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