Zero chlorine reading

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
dodgegirl48
Pool Newbie
Pool Newbie
Posts: 2
Joined: Wed 25 Apr, 2012 19:54
My Pool: Paragon 27'x52 aboveground pool
Location: Pa.

Zero chlorine reading

Postby dodgegirl48 » Thu 24 May, 2012 19:31

I just had my water tested and was told to add 4 jugs of trichlor,some soda ash for ph level and calcium chloride.After adding everything by the instructions i circulated for 4-6 hours and then tested the water.Chlorine was very high and ph was way too high.I circulated overnight and tested in morning and everything was still high.I had some PH minus so i added some and brought ph level to normal and decided the chlorine would come down on its own.Well later about 6:00 p.m. i thought i would test it again and it had a zero chlorine reading.Both free and total were zero but everything else seemed to read okay.I don't know what happened.Should i have had tablets in the skimmer.Should i get more jugs of chlorine or just use tablets to raise it up? Any help appreciated. Thanks!


chem geek
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Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Zero chlorine reading

Postby chem geek » Fri 25 May, 2012 15:41

If you are using a DPD chlorine test, the kind that turns pink/red when chlorine is present, then this can bleach out at high chlorine levels. Use either an OTO chlorine test, the kind that turns yellow when chlorine is present (or orange or red if chlorine is very high) or use a FAS-DPD chlorine test as in the Taylor K-2006.

If your chlorine level is truly zero, then add more chlorine. If the chlorine loss is during the day only, then you probably don't have enough Cyanuric Acid (CYA) in the pool. If the chlorine loss is overnight, then you may have algae growing in the pool though that seems unlikely if the chlorine level was truly high.
OzCop
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Joined: Fri 25 May, 2012 21:19
My Pool: 22x38 dive pool, gunnite construction, DE filter
Location: Highland Village, TX

Zero chlorine reading

Postby OzCop » Fri 25 May, 2012 21:48

Hi, I am new to the fourm, so please be patient...I have a similar issue and the answer to this one may solve mine. We had some algae issues, black algae spots, and followed the pool supplier's (Leslie here in north TX) advice on getting rid of the algae. I backflushed, blasted fresh DE, used soda ash, trichlor, and other additives as directed, as well as added 5lb. of shock as directed. Tested 24 hours later and it appeared my acid level was low so I added another 2 gallons. I have a chlorine tablet dispencer that holds nine, 3inch tablets, and I opened it to max distribution. Water looks ok, but is by no means clear, and this is a full 48 hours later. Testing, using the strips, according to the strips I had zero chlorine and and all other colors on the strip were off the chart negative.

Could it be the Chlorine levels are too high, and perhaps I need to test using the method suggested above? Any help much appreciated...
chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Zero chlorine reading

Postby chem geek » Sat 26 May, 2012 03:00

Possibly, though your continued use of Trichlor probably means that your CYA level is very high. Test strips are worst at measuring CYA. Do yourself a favor and get yourself a proper test kit, either the Taylor K-2006 or the TFTestkits TF-100 .

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