ORP only goes up with non-chlorinating shock

lambdasig

New member
Jun 10, 2018
3
Clarendon Hills, IL
My Hayward system in my SWG pool seems to run the Chlorinator indefinitely as the ORP in my pool actually drops when the cell is triggered. When left unchecked, the FC skyrockets and a neutralizer is required to be safe to swim. I understand ORP and FC are not one in the same, but there is a trigger to turn on the chlorinator when ORP falls below a threshold like 520 for example. The only way I have found to increase ORP is to add in a non-chlorine oxidant shock like Leslie’s Fresh N Clear. The Hayward rep and pool company haven’t been helpful in answering. I am told the higher ORP is going to help the FC be more effective. I think if I didn’t use Fresh N Clear my ORP would likely be 430 or less and I am advised not to do that.

Anyone able to help me diagnose or run into this?
 

joboo7777

Bronze Supporter
Aug 8, 2020
244
McKinney, TX
Pool Size
15568
Surface
Plaster
Chlorine
Liquid Chlorine
What is your CYA at? Anything above 30ppm can cause ORP probes to read significantly lower readings. This presents another issue since you typically need to keep cya higher when running a SWG.

I have a thread on the Hayward Sense & Dispense system I believe you are referring to. Bottom line is if you are dosing liquid chlorine using the sense and dispense system you are fine since you can lower CYA to just about 30ppm and it will work well. For SWGs… not so much. There are others on the board having issues with ORP probes running SWGs due to the higher CYA levels.

hope this helps.


 
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lambdasig

New member
Jun 10, 2018
3
Clarendon Hills, IL
thx for reply. My CYA is 30 or less, as I don’t add stabilizer given my pool is covered 99% of the time and always when not in use or cleaning. Ph is 7.6 and in keeping balanced water with TA and CH, etc, this is a consistent experience with my salt cell activating when ORP drops and continues to drop despite FC going up to 20+ if I didn’t catch that chlorinator was running non-stop… my system is not sense and dispense), but rather electrically charged salt cell that reacts with the salt water to generate chlorine.
 

joboo7777

Bronze Supporter
Aug 8, 2020
244
McKinney, TX
Pool Size
15568
Surface
Plaster
Chlorine
Liquid Chlorine
the Hayward OmniLogic system is the base unit. Then there is a control panel/Cell that connects the probes to the OmniLogic. That’s the Sense & Dispense component. if you look at the attached picture you will see the OmniLogic on the right and the sense and dispense connect to it on the left.

I wish I could help you more. Unfortunately my implementation of the system uses Liquid chlorine dispenser using a dosing pump as I don’t have a SWG.

I’m surprised the Hayward rep was not helpful. My local rep in TX is very responsive with a direct channel to engineering. I would go back to rep and insist on help.
 

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Charles Bezzina

Well-known member
Jul 10, 2021
123
Sydney Australia
Pool Size
38000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
Hello lambdasig. It seems I may have a similar problem.
Mine is a new Hayward aquarite+ with something similar to sense and dispense integrated in to the chlorinator. The pH and ORP connectors are provided on the chlorinator, but they are inactive untill you insert the 2 optional circuit cards (one for pH and one for ORP) presumably containing additional firmware.

I purchased both the upgrades. pH seems to work but ORP is not working. Whenever my filtration pump runs the ORP reading goes down. If the cell is producing chlorine the ORP reading drops faster. After 24 hours with the cell producing, the unit displays 0mV ORP.

After I discovered the chlorinator stuck in this positive feedback loop I contacted Hayward. In the interim they requested i just let the pump run for 8 hours a day with the cell unplugged, only reconnecting the cell when the fc drops too low. When I was doing this, my ORP reading would recover from some low value to around 730mV after 3 days.

After putting up with these shenanigans for two months I have plugged the cell back in and configured the ORP threshold to 1000mV and set the unit to run at 25%.

Hayward suggest my ORP probe might be faulty, but they won't come and look at the unit due to current covid lockdowns (I totally agree with them on this one.. Sydney is a mess with Delta atm) Hopefully they will sort it soon though.

I would really like to know if anyone else has seen similar behaviour and if they were able to rectify it?
 

scottts

Gold Supporter
Nov 13, 2019
202
Gilbert, AZ
I have the Pentair intellichem with a intellichlor swg. I cannot run the system trying to use a dose to an orp set point methodology. I had to switch to a timed mode running my cell on for about 12 minutes and off for about 5.

When the cell runs it generates hydrogen which strongly lowers ORP. So the on off timing gives the system a chance to offgas some of the hydrogen so the system doesn’t run away.
It still doesn’t work great but at least it doesn’t go into an over chlorination condition.
 

Charles Bezzina

Well-known member
Jul 10, 2021
123
Sydney Australia
Pool Size
38000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
Hi scotts. I've seen other posts that associate hydrogen produced by the cell with a drop in ORP.

I don't disagree, but I'm confused as to why my ORP goes down even when the cell has been disconnected for over a week!

Have you ever tried running your pump with the cell disconnected?
 

joboo7777

Bronze Supporter
Aug 8, 2020
244
McKinney, TX
Pool Size
15568
Surface
Plaster
Chlorine
Liquid Chlorine
Hi scotts. I've seen other posts that associate hydrogen produced by the cell with a drop in ORP.

I don't disagree, but I'm confused as to why my ORP goes down even when the cell has been disconnected for over a week!

Have you ever tried running your pump with the cell disconnected?
Charles, Can you take a picture of the Probes and how they are installed? Curious to see if they are the same as what I have with the sense and dispense.
 

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scottts

Gold Supporter
Nov 13, 2019
202
Gilbert, AZ
Hi scotts. I've seen other posts that associate hydrogen produced by the cell with a drop in ORP.

I don't disagree, but I'm confused as to why my ORP goes down even when the cell has been disconnected for over a week!

Have you ever tried running your pump with the cell disconnected?
Are you chlorinating in some other way when the cell is off? If not the ORP will drop because the FC drops. ORP is also very sensitive to pH. If your pH rises ORP will drop. If your water temp changes, ORP will change. ORP is just the instantaneous redox balance in the water. There's lots of things that affect it.
 

Charles Bezzina

Well-known member
Jul 10, 2021
123
Sydney Australia
Pool Size
38000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
And a photo of the plugs going straight in to the chlorinator. I don't have a photo of the insides, but there are two little boards that went inside.( It's a really neat design, I think)
 

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Charles Bezzina

Well-known member
Jul 10, 2021
123
Sydney Australia
Pool Size
38000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
Scottts, there's no other source of chlorine. I may not be describing what I see well, so let me explain differently. Note that the cell was unplugged when I was recording these.

One day..
6:30am pump turns off.
6:30am, ORP 629, pH 7.7
7:30pm, ORP 729, pH 7.7
10:30pm pump turns On.
Following day..
6:30am pump turns Off
6:30am, ORP 688, pH 7.7
8:30pm, ORP 730, pH 7.7
10:30pm pump turns on.
Etc.

Also, it's winter here with very low UV. When I run the chlorinator I get FC over 5 and it takes two weeks to go down to 3 with the cell disconnected.
 

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Charles Bezzina

Well-known member
Jul 10, 2021
123
Sydney Australia
Pool Size
38000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
I realise I keep mentioning that the cell is disconnected, but as I said the ORP goes down even faster with the cell connected! Crazy huh..
 

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joboo7777

Bronze Supporter
Aug 8, 2020
244
McKinney, TX
Pool Size
15568
Surface
Plaster
Chlorine
Liquid Chlorine
And a photo of the plugs going straight in to the chlorinator. I don't have a photo of the insides, but there are two little boards that went inside.( It's a really neat design, I think)
Hmm, I couldn't find this model on Hayward's site. Is that the AquaRite S3 Omni? They mentioned on the site it was coming summer 2021.
 

scottts

Gold Supporter
Nov 13, 2019
202
Gilbert, AZ
Scottts, there's no other source of chlorine. I may not be describing what I see well, so let me explain differently. Note that the cell was unplugged when I was recording these.

One day..
6:30am pump turns off.
6:30am, ORP 629, pH 7.7
7:30pm, ORP 729, pH 7.7
10:30pm pump turns On.
Following day..
6:30am pump turns Off
6:30am, ORP 688, pH 7.7
8:30pm, ORP 730, pH 7.7
10:30pm pump turns on.
Etc.

Also, it's winter here with very low UV. When I run the chlorinator I get FC over 5 and it takes two weeks to go down to 3 with the cell disconnected.
In my pool orp rises as the pool gets shaded and drops as the sun hits it. Something to do with the chlorine cya interaction to sunlight. The less cya I run the greater the orp swing. It’s a rhythm that repeats every day. I run my pump 24/7. It happens even in the winter here as well. Also if I run my waterfall orp rises a lot. So many things affect it. Today my orp ranged from a high of 665 just before sunrise to 570 just prior to when the sun ducks behind some big trees and shades the pool. My cya is 15 and fc was 5 ppm.
 

Rob Snowden

Member
Oct 4, 2020
11
Charlotte, NC
Pool Size
15000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite Pro (T-15)
What is your CYA at? Anything above 30ppm can cause ORP probes to read significantly lower readings. This presents another issue since you typically need to keep cya higher when running a SWG.

I have a thread on the Hayward Sense & Dispense system I believe you are referring to. Bottom line is if you are dosing liquid chlorine using the sense and dispense system you are fine since you can lower CYA to just about 30ppm and it will work well. For SWGs… not so much. There are others on the board having issues with ORP probes running SWGs due to the higher CYA levels.

hope this helps.


This is a great response. I have a S&D system running in tandem with a SWG as well. My ORP was never higher than 5mlv.

The best fix is simply to revert back to the manual adjustment settings. It is easy to do and your manual will tell you how to configure the settings.

I do, however, like the PH side of the system, but be sure to have your pool balanced first. Otherwise you will be fighting the fluctuations between PH and ALK.

Thanks,

Rob
 

joboo7777

Bronze Supporter
Aug 8, 2020
244
McKinney, TX
Pool Size
15568
Surface
Plaster
Chlorine
Liquid Chlorine
In my pool orp rises as the pool gets shaded and drops as the sun hits it. Something to do with the chlorine cya interaction to sunlight. The less cya I run the greater the orp swing. It’s a rhythm that repeats every day. I run my pump 24/7. It happens even in the winter here as well. Also if I run my waterfall orp rises a lot. So many things affect it. Today my orp ranged from a high of 665 just before sunrise to 570 just prior to when the sun ducks behind some big trees and shades the pool. My cya is 15 and fc was 5 ppm.
Interesting, That’s a much different cadence than mine. I run my pump from 8am - 8pm and When Pump turns on my first reading is typically around 730/740 and it’s the around the same when the pump turns off at 8pm. I keep my FC around 2-3ppm
 

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