Outrageously high chlorine reading

mariane

Bronze Supporter
LifeTime Supporter
May 8, 2012
1,384
Metro Detroit, Michigan
Pool Size
11500
Surface
Vinyl
Chlorine
Liquid Chlorine
Hi everyone. I discovered this site last year and have learned a lot about caring for our pool. Just starting BBB at the end of last season. Now opening up pool this year and tested chemical levels after bringing water level up to full and running pump for 2 days.
With TF100 test kit the levels are: pool store levels are:
chlorine: orange colored
pH: 7.2-7.5 pH: 7.9
FC: 97.5? FC: 9.6
CC: .5 CC: they don'tmeasure this specifically but am I right that it's .4
TC: 98? TC: 10
TA: 90-100 TA: 85 TA adjusted: 80
CH: 160-190 CH: they test TH: 113
CYA: 40 CYA: 17
Borates: 30-50 Borates: 38

When doing the CDT, I was putting in so many drops with no change in test color. I had read somewhere to add regular water and then multiply the drops used by how much extra water added. Therefore I used 30 ml of water (10 ml from the pool) and it took 65 drops to change color back to clear. Did the math 65 x 3 then divided by 2 to get 97.5. Did I do this right?

In March the weather was in the 80's here for several days and I was not about to open the pool then. Advice from the guy at the pool store was to put in 4 gallons of 12.5% chlorine so algae would not grow. I think that's why the chlorine levels are so high, but is 97.5 possible or did I do the math wrong? Any thoughts of what to do? The vinyl liner does not look bleached and the water is clear. Some dirt and stuff on the bottom but no algae. LOL.

Thanks for all the help you give to pool owners. BBB is the way to go. (Got the pool store levels just for kicks :lol: )
 
Using the pool calculator it looks like 4 gallons of 12.5% only gets you to 40 ppm in a 13,000 gallon pool. How long did you wait after adding chlorine before testing?

Edit: sorry, I just reread and found where you mentioned running the pump for 2 days. It doesn't seem possible that your chlorine could be that high. How many times did you try the test?
 
Using dilution like that is only valid if your non-pool water is completely chlorine free. Commonly tap water has chlorine in it. Also the OTO test showing orange suggests a level of 15 to 30 (or maybe 40). It turns brown if FC is actually anywhere near 100.

Even an FC level of 15 would be higher than I would expect after two days without any chlorine additions unless the CYA level is actually higher than you think it is.
 
macgulley, thanks for the reply. The chlorine was added in March when the water level was low for the winter and we are just now opening the pool. I started adding tap water and brought the water level back up to full this past weekend then started running the pump on Tuesday. I tried the test twice since then. Crazy numbers!

JasonLion, thanks and yes I used tap water and not distilled water to dilute the test.
So, orange is high, and its good to know brown would be worse. :)
We put the cover on to keep out the seeds from the trees and the birds dodo. Should I take the solar cover off and let the excess chlorine burn off until the levels get to 2-3? I did go to the pool store for results just for kicks. Their numbers were mostly different from mine and they recommended (which I will NOT follow) chem out to lower the chlorine level. What do you all think?

Thanks again for all the help given to oodles of pool owners and now especially me. :wave:
 
The solar cover would explain why the FC level hasn't come down much. Yes, taking off the cover for while will lower the FC level fairly dramatically. I would expect it to take two days to get to normal swimming levels.
 
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