High Chlorine, Low ORP

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
gellisdds
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My Pool: 29K gal IG salt, plaster/pebble, Var speed pump, cartridge filter, Aquapure chlorine gen, Chemlink 1900, Aqualink
Location: United States

High Chlorine, Low ORP

Postby gellisdds » Tue 21 May, 2013 10:54

I have read other posts on high chlorine but they do not address my particular problem. I have a 29,000 gallon in ground salt pool with Jandy equipment, Chemlink 1900 controlling the ORP and the pH, an Aquapure chloring generator. All of this is ultimately controlled with my Aqualink and using the iaqualink on an i-pad.

My concern is... the pool is about a year old. My chlorine both total and free are so high the pool supply company stops at 5 and I am much higher than that when it says I should be down around 3 I think. My confusion is this. I cannot seem to bring it down. I get conflicting advice. One technician said that since the ChemLink is controlling the ORP then the Aquapure should be set at 100% so it is giving 100% when it is called upon to add chlorine. Someone else told me that it should never be at 100%.

My ORP is 610 currently and I have read that it should be at least 650 for proper sanitization but I would think that with such a high chlorine that my ORP should be higher. The Chemlink is asking the Aquapure to produce chlorine because it wants the ORP to be at least 650. But the pool already has too much chlorine (there is no odor or taste of chlorine though, and no eye burning). I also run the pool pump about 12 hours a day right now (Texas). So I am not sure if I am missing something, or if my Chemlink is having issues or I have a bad sensor or may be all of the above. I turned the Aquapure to 0% yesterday and am waiting a few days to see if the chlorine comes down. Does anyone have any advice? I can give more information if needed.

Thanks very much.


gellisdds
Pool Newbie
Pool Newbie
Posts: 3
Joined: Tue 21 May, 2013 10:32
My Pool: 29K gal IG salt, plaster/pebble, Var speed pump, cartridge filter, Aquapure chlorine gen, Chemlink 1900, Aqualink
Location: United States

High Chlorine, Low ORP

Postby gellisdds » Tue 21 May, 2013 11:02

Added information to my original post,

water tested on 5/19/2013:

fc = higher than 5
cc = higher than 5
ph = 7.5
ta = 90
ch = 375
cya = 40
chem geek
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High Chlorine, Low ORP

Postby chem geek » Wed 22 May, 2013 01:41

The Cyanuric Acid (CYA) binds to most of the chlorine while the ORP is mostly measuring something proportional to the unbound chlorine and more specifically the hypochlorous acid concentration. Nevertheless, 5 ppm FC with 40 ppm CYA at pH 7.5 would normally give an ORP of nearly 700 mV with a Chemtrol sensor or 660 mV with an Oakton sensor. The ORP varies by manufacturer and even by sensor. You can use it to set a setpoint for control of the chlorine level, but I wouldn't use it as an absolute measure unless you get a more reliable sensor. Also check with the manufacturer since CYA can foul some of the membranes for some of the sensors.
gellisdds
Pool Newbie
Pool Newbie
Posts: 3
Joined: Tue 21 May, 2013 10:32
My Pool: 29K gal IG salt, plaster/pebble, Var speed pump, cartridge filter, Aquapure chlorine gen, Chemlink 1900, Aqualink
Location: United States

High Chlorine, Low ORP

Postby gellisdds » Wed 22 May, 2013 06:03

So essentially what you are saying is that I probably have a bad sensor?
chem geek
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High Chlorine, Low ORP

Postby chem geek » Wed 22 May, 2013 21:00

Either bad or it needs to be cleaned. But also check with the manufacturer for what they expect if you have an active chlorine level equivalent to 0.1 ppm FC with no CYA -- ask them what ORP do they expect in that situation, because that's the rough equivalent if you have 5 ppm FC with 40 ppm CYA.

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