Would this ORP correlation be during the day or at night? With a CYA of 30 I still get 20-30mv ORP decrease when the sunrises.
pH sensors that don't have to be calibrated
- Thread starter Katodude
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VinceL
LifeTime Supporter
The temperature absolutely affects the ORP. For example, today, I had an ORP reading of 645 at 10 am with cloudy conditions. After the sun had been out for a couple of hours, the water temperature was up about 5° and the ORP was down to 600. I tested my water today, and my CYA was also 30. We have had heavy rains over the last few days and lost a lot of water through the overflows. I added baking soda, calcium chloride, salt, and CYA to the pool today.
If you search through the Deep End section of the TFP forum, you can find some serious discussions about ORP involving people who apparently have a great deal of expertise in chemistry.
This is what I tried to do last year (see my post above). I created a sunlight/temp detector. pH and ORP both moved with temp, but not in a very predictable way. Part of the problem was that I had >100 CYA, so the ORP really was useless.
If you get it working, please post your curves!
- Aug 22, 2017
- 2,591
- Pool Size
- 15000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
I am doing the reading on ORP now, and I am not very optimistic about it. I also might be getting a little ahead of myself. The pH sensor arrives at the end of this week and that will be more fun to play with for a while.
Depending on boredom levels you never know. It might be a fun experiment to take up. I was really hoping to find some type of formula that would be something like:
FC = CYA * temp * pH * ORP, or you get the point, put in all the variables and get an approximation of FC, but not sure that is going to be possible.
Depending on boredom levels you never know. It might be a fun experiment to take up. I was really hoping to find some type of formula that would be something like:
FC = CYA * temp * pH * ORP, or you get the point, put in all the variables and get an approximation of FC, but not sure that is going to be possible.
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The high-CYA ORP “sensitivity washout” seems to be an issue that is ?impossible? to solve for outdoor, full-sun pools here in the desert (or anywhere). I usually run my pool around CYA=50 and still have substantial chlorine loss throughout the day. Because I plan on refilling my pool this fall, I am going to do some experiments with CYA around 80 to see how it impacts my chlorine needs. But it is hard for me to imagine that I could run CYA=30 or less based on the half-life tables of free chlorine that are in the DeepEnd, without dumping in a gallon+ of chlorine a day. For me, that kinda defeats the purpose of the monitoring in my mind which is to add the minimum/appropriate amount to keep the pool in the safe zone.
Personally, I was hoping that ORP could provide “danger, danger” notifications if FC drops to really low levels (and/or possibly super high levels) due to issues such as a Stenner pump tube springs a leak or added liquid chlorine was non-potent (I check the dates but still had 6 gallons like that recently). Because these goals look to be difficult/impossible (from most everything I have read), ORP is one of the last things I ‘might’ try to tackle as part of my project.
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- Aug 22, 2017
- 2,591
- Pool Size
- 15000
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- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Same here in South Florida. I can get by with a CYA of 60, but life is much better with it closer to 70-80, especially for me since I have a SWG. My pool also has a southern exposure so I get full sun all day.
But as I think about it, I like your idea. If we can figure out a way to make ORP some sort of an early warning system. "Hey buddy check your FC!!" that would be enough.
But as I think about it, I like your idea. If we can figure out a way to make ORP some sort of an early warning system. "Hey buddy check your FC!!" that would be enough.
Definitely watching with interest. 
Since I never opted for the IntelliChem (had possibilities but fell short of the mark imo), I have two available 1/2 "taps" available in the plumbing that are just waiting for an opportunity such as this.
Also, a big fan of keeping a target of 75ish on the CYA (but also with SWCG).
That target number has seemed to really work out for me.
Not too concerned if it happens to drop down into the 60's or even 50's in the winter, but if I don't keep it in the 70's in the summer, I have noticed that I'm required to bump up the output of the SWCG in order to keep FC at an acceptable level.
Thanks for sharing the continuing info and experiences on this front.
r.
Since I never opted for the IntelliChem (had possibilities but fell short of the mark imo), I have two available 1/2 "taps" available in the plumbing that are just waiting for an opportunity such as this.Also, a big fan of keeping a target of 75ish on the CYA (but also with SWCG).
That target number has seemed to really work out for me.
Not too concerned if it happens to drop down into the 60's or even 50's in the winter, but if I don't keep it in the 70's in the summer, I have noticed that I'm required to bump up the output of the SWCG in order to keep FC at an acceptable level.
Thanks for sharing the continuing info and experiences on this front.
r.
I did start with CYA at 50 last October. As it has slowly decreased, now down to 30 (just), the ORP swings have become more predictable and smaller in amplitude. Stable pH is a MUST. Intellichem really helps with that my daily pH ranges from 7.45 to 7.55 (7.5 set point). My water temp is ranging from about 85-90F right now. So far the IC-40 can keep up with FC demand at a 50% production rate.
I think my biggest problem now is the Hydrogen H2/H+ redox couple. ANY dissolved H2 (ANY - and I know H2 isn't that soluble in water) has a large negative ORP. I can see this happening when my SWCG goes offline - ORP rises very quickly over the next couple of hours. Here's an article on this I found - H2 Sciences. This is about H2 water creation but the info was interesting.
If anyone knows how to reduce the generation of H2 in the SWCG cell, I'm all ears. Could metals in the water, say copper, enhance H2 production? I suspect a copper algaecide may have been added at the startup of the pool by the PB when I wasn't there.
I think my biggest problem now is the Hydrogen H2/H+ redox couple. ANY dissolved H2 (ANY - and I know H2 isn't that soluble in water) has a large negative ORP. I can see this happening when my SWCG goes offline - ORP rises very quickly over the next couple of hours. Here's an article on this I found - H2 Sciences. This is about H2 water creation but the info was interesting.
If anyone knows how to reduce the generation of H2 in the SWCG cell, I'm all ears. Could metals in the water, say copper, enhance H2 production? I suspect a copper algaecide may have been added at the startup of the pool by the PB when I wasn't there.
- Aug 22, 2017
- 2,591
- Pool Size
- 15000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Well back to the pH probe for a minute. Just ordered 3/4" saddle clamp, 7/8" hole saw, deburring tool, and a new stopper for my outdoor sink (not related but it was part of the order). ph stuff supposed to arrive Thursday so I will post pictures of the install.
Cool. BTW, my pH probe has been in use since October last year. Never cleaned it, test it against the drops every week, still dead on. Hope your probe is as reliable.
scottts
I'm happy (and a bit jealous too lol), that the IntelliChem on the pH side is working out so well for you.
I so wanted an IntelliChem at one point (not for the FC side really due to the ORP issues, but for the pH side of it), as I had become disheartened by the IntellipH. The ipH does what it is supposed to do just fine, but I wanted much more (remote) automation when it comes to MA dosing and also pH capture.
But then I discovered that IntelliChem would not allow an OP to target any higher than 7.6 on pH. Rats... My pH just likes to live at 7.7-7.8 in the summer and 7.8-8.0 in the winter. That is just the way my pool rolls and I found through lots of advice here, that this fact was just fine. And all my other numbers seem to stabilize at those pH numbers as well.
Also, I kind of took the position that "how dare Pentair dictate to me what they think that my pH ceiling should be". IMO, that's my call, not theirs. So now, just like I have already done regarding the Pentair web client/mobile apps for the IntelliCenter, I will need to look to the "darkside", in the future for pH (and maybe even FC) automation.
Thanks...
r.
Yeah the pH high limit was initially a problem for me too. Initially, and through the cold winter, my CH was at about 250 and not rising much. I knew when summer came it would rise so I left it. pH really wanted to be 7.7 or 7.8 at that point. Now with my CH at 525 and rising, I'm having to bump pH down to keep LSI (what the intellichem uses) slightly negative. So right now it is not a problem, but yeah, I think they should loosen up on the upper pH limit. I think they may be following some standard/regulation for pH limits.scottts
I'm happy (and a bit jealous too lol), that the IntelliChem on the pH side is working out so well for you.
I so wanted an IntelliChem at one point (not for the FC side really due to the ORP issues, but for the pH side of it), as I had become disheartened by the IntellipH. The ipH does what it is supposed to do just fine, but I wanted much more (remote) automation when it comes to MA dosing and also pH capture.
But then I discovered that IntelliChem would not allow an OP to target any higher than 7.6 on pH. Rats... My pH just likes to live at 7.7-7.8 in the summer and 7.8-8.0 in the winter. That is just the way my pool rolls and I found through lots of advice here, that this fact was just fine. And all my other numbers seem to stabilize at those pH numbers as well.
Also, I kind of took the position that "how dare Pentair dictate to me what they think that my pH ceiling should be". IMO, that's my call, not theirs. So now, just like I have already done regarding the Pentair web client/mobile apps for the IntelliCenter, I will need to look to the "darkside", in the future for pH (and maybe even FC) automation.
Thanks...
r.
You could tweak the ph sensor and crank in an offset so that when it read 7.6 is was actually 7.7 or 7.8 but then the LSI calculations would be wrong.
Good points.
That is always the issue with our muni water around here. Starts out good but just keeps adding that hardness over time. I had finally had enough of that whole scenario over the years and motivated myself to plumb my pool auto-fill line to the house softwater line. Ever since I did that, my CH has been dropping and appears to have stabilized around 400-450 now and that must be the reason now that the pH likes to live just a tad higher I guess.
Thanks...
r...
- Aug 22, 2017
- 2,591
- Pool Size
- 15000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
So, the pH sensor and accessories arrived today. The only thing that is missing is a $4 part that will allow my to hook it up to my DIY controller. But no big deal the control board has a big LED display that I can use in the meantime.
Speaking of the control board it is BIG, much bigger than I thought. I will be able to make it fit but it will take a little squeezing. At some point I will tear down the innards and do a little re wiring and I should be able to free up a bunch of space, but that is a project for another time.
I should be able to install it sometime this weekend and look forward to reporting back with pictures.
I plan on installing it on one of the skimmer lines. Its one of the few places I think I have room without some major replumbing.
Speaking of the control board it is BIG, much bigger than I thought. I will be able to make it fit but it will take a little squeezing. At some point I will tear down the innards and do a little re wiring and I should be able to free up a bunch of space, but that is a project for another time.
I should be able to install it sometime this weekend and look forward to reporting back with pictures.
I plan on installing it on one of the skimmer lines. Its one of the few places I think I have room without some major replumbing.
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Kato, a couple thoughts:
1) your return side plumbing IS tight (after the filter)...but...if/when I install a pH probe, I will probably have it on that side just to avoid any debris,etc. That wouldn’t be easy in your case unless you make some changes...something to consider.
2) calibration...not sure what the single point calibration actually does inside your probe hardware probe, but I will consider a software calibration for any eventual probe...use whatever current reading I get using the pH color tubes to adjust the value being read from the sensor. That would probably provide enough accuracy for my purposes (but probably wouldn’t for ORP probe consistency).
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- Aug 22, 2017
- 2,591
- Pool Size
- 15000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Yeah, I went back and looked and there is absolutely no where I can put this after the filter. Unless I re plumb the whole thing, and not willing to do that yet. Anyway this sensor is supposed to have a square probe which makes them apparently less susceptible to damage. I guess we will find out.
Anyway bench tested it today and it works. They say you dont need to calibrate it out of the box, but I have 3 calibration solutions and I might do it anyway. Tested my pool 7.7 and my fill water 8.4. Excited to get it plumbed in this weekend.
Anyway bench tested it today and it works. They say you dont need to calibrate it out of the box, but I have 3 calibration solutions and I might do it anyway. Tested my pool 7.7 and my fill water 8.4. Excited to get it plumbed in this weekend.
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- Aug 22, 2017
- 2,591
- Pool Size
- 15000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
So an update. Just before I was about to drill the pvc to put the 3/4” clamp on something inside me said double check. I took the pH sensor and tried to insert it into the saddle clamp and it does not fit. I am going to have to go to Lowes today and just get a T connector and cut and glue pipe. I was hoping to avoid this but it looks like I will not have a choice.
Nice catch...nothing more frustrating than nearing completion of a job and realizing one of the basic premises was incorrect...haha. I’ve had that happen many times. Have you tested it with pool water and does it “match” the color tests?
- Aug 22, 2017
- 2,591
- Pool Size
- 15000
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- Plaster
- Chlorine
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- SWG Type
- Hayward Aqua Rite (T-15)
I have tested it both with pool water and my tap water. Both match the Taylor color tests. In fact tap water just goes bright pink for Taylor which maxes out at 8.2. The pH sensor gave me an 8.4.
- Aug 22, 2017
- 2,591
- Pool Size
- 15000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
So it turns out that the probe also does not fit in a T reducer, but it is much closer. A little work with the dremel and got it to fit. But it is not a great design that the probe section is almost the same size as the NPT fitting.
Now I just have to cut the pipe and insert the T. Something I have never done before, so I am a little concerned. Should be able to work up the courage this week, and then have a pool guy on speed dial in case I screw it up.
Now I just have to cut the pipe and insert the T. Something I have never done before, so I am a little concerned. Should be able to work up the courage this week, and then have a pool guy on speed dial in case I screw it up.