Can’t get Free Chlorine up? Metal issue?


New member
Apr 27, 2020
Minneapolis, MN
I’m an ignorant new owner of a home with a pool. Been trying to follow the trouble free pool wisdom.
Had/have algae after opening started SLAM process. I put crazy amounts of liquid chlorine/bleach in over two days (approx. 30 gallons) because the free chlorine reading kept showing approximately 0.5-to less than one whenever tested. Started to clear some but turned a lighter more neon green and less murky and no longer brown/green. There still appears to be some algae but after some research I’m assuming the color change is more about metal content. I’m still waiting for the delivery of the recommended test kit, so trying to diagnose as best I can until it arrives. But I even tested for free chlorine within 15 minutes of adding 4 gallons of bleach and there was hardly any increase in free chlorine reading. (Based on a subpar testing kit.)
Numbers below are from pool store as I just had to get another reading to compare until my kit arrives.
Do I keep adding bleach? (I’ve almost bought out the store). Is a high metal count affecting my chlorine treatments? Should I be treating the metal issue (assuming there is one) before continuing to shock?
Appreciate any help that can be offered. Thanks for the site.

20,000 gallon vinyl pool
FC 1.18 (even after shock)
TC 14.18
PH 6.7
Hardness 93
Alkalinity 109


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Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Welcome to TFP! :wave: At this point, I wouldn't do much until your test kit arrives. Take no chances. But here are some things to consider:
- Post a full set of results with your kit once it arrives. In the meantime, review the Extended Test Kit Directions – Trouble Free Pool
- Probably no sense adding too much bleach based on what I'm hearing. Maybe a gallon or two a day just to try and keep things from getting much worse. I would stock-up on some more so you're ready for more of the SLAM.
- Other than the bleach though, don't add anything else until we see your test results.
- At opening, did you add anything to the water? Stabilizer, algaecides, anything?
- Metals won't impact the SLAM. Your second pic does seem to show a reaction to metals, but the SLAM is always first, then letals treatment.
- Are you on a well, or is your city known for having iron/copper?


New member
Apr 27, 2020
Minneapolis, MN
Thank you for the response.

I will post test results as soon as I receive the kit.

As for the water question, I do believe our city water has a fair amount of iron and/or copper content.
And when opening the pool there was a pool company who did the initial open (as part of our purchasing this home- not necessarily my choice), so they did add some things as an initial shock. I was told after the fact that it was roughly 6-10 pounds of strong granular chlorine, also 4 large chlorine tablets into the skimmer and a 3 in 1 product called Unique (an algae use, clarifier, s equestrian agent).

Thanks again for your help
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