ORP accuracy/reliability, worth investing or not?

jpcolin

Member
Aug 1, 2016
17
Belgium
Hello,

I'm still in the proces of choosing my pool automation, and i would like to automate as much as possible.
So i was thinking about pentair intellitouch and intellichem (with liquid chlorine dosing not SWG), but i read a lot of complains about ORP sensing (for chlorine regulation), not only from Pentair but other brands alslo, is it worth investing in this? Most stories i have read, they say that after a while struggeling they just disconect the ORP reading and do it manualy.
So what is your advice?

Thank you
 

dschlic1

LifeTime Supporter
Oct 5, 2007
564
Valrico, FL
ORP will work, but you must keep a very low level of CYA. No more than 20 ppm. Above that amount, ORP will not change in a reliable manner with respect to free Cl.
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,968
SouthWest Alabama
The downside of trying to maintain a lower CYA level is that you use a lot more bleach maintaining proper FC. Especially if you live in a sunny climate.

Even with a lower CYA level you're not guaranteed that ORP will work reliably over time.
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,968
SouthWest Alabama
I've read a little about the amperometric probes, but haven't seen any in service. They're supposed to be compatible with CYA. The downside is that they're pretty expensive.

I don't know of any pool automation systems that use them. There could be some that I haven't heard of.
 

Patrick_B

TFP Expert
LifeTime Supporter
Jun 7, 2011
14,999
Midland TX
The industrial ones are very finicky on calibration I know that much. I agree with Bama, and I don't think the technology has made it down to pools yet, but I don't keep up with it either.
 

Ahrand

Member
Oct 12, 2016
14
Belgium
ORP kinda works if :
- CYA is under 20
- probes are recalibrated every year
- probe housing is keept clean (no debris)
- new probes every 3-5 years
- with pool closing: dismantled and stored in storage fluid over winter
 

jpcolin

Member
Aug 1, 2016
17
Belgium
ORP kinda works if :
- CYA is under 20
- probes are recalibrated every year
- probe housing is keept clean (no debris)
- new probes every 3-5 years
- with pool closing: dismantled and stored in storage fluid over winter
Well that would work for me! Can anyone confirm?

So Ahrand that your case, you're happy with it, i see you are from Belgium too?
I would love to have more info about your setup (Logo Siemens), i'm actualy looking to "make" my own automation too.
 

Ahrand

Member
Oct 12, 2016
14
Belgium
So Ahrand that your case, you're happy with it, i see you are from Belgium too?
I would love to have more info about your setup (Logo Siemens), i'm actualy looking to "make" my own automation too.
Actually, I switched it off after 3 seasons fighting with it...
At the top of summer you need more than 20CYA, otherwise the sun will burn more chlorine tegen the swcg can make.
I trust my Siemens automation more now.
Are you Dutch speaking ? Send me a private message.
 

dradam

LifeTime Supporter
Mar 10, 2013
142
maryland
I wrote an article in diy pool automation with Pentair. I have been happy with the coordination of their system. ORP probes as you know are an indirect way to monitor FC. These probes are finnicky. I run a very low flow 15 gpm 24/7 and try to keep my pool at a unifor temperature-- all automated. With that I find orp to be consistent. I have not yet seen cost effectve FC probes. Search the forum for DIY pentair Pool automation and you can find the article. hope it helps.
 

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