ORP and PH automation with Hayward HL-CHEM and Omnilogic

Jump to latest Follow Reply
M

morejp4

0
May 24, 2016
22
College Station, TX
All,

Just yesterday ordered up parts for this years pool project. I have the Hayward Omnilogic system as my pool panel, and have 2 relays that are currently not being used. I ordered yesterday the HL-CHEM system (ORP and PH sensors in a test well that connect to the main panel), as well as a 12 GPD Rola-Chem pump, and the Hayward AC003 residential CO2 system.

I decided on the AC003 CO2 system because it appears that it comes with an actual gage to see what the bottle pressure is, as well as the ability to change the flow rate into the system. I have already purchased a 50 LB bottle of CO2 from a local welding supply, and I will be able to do a bottle exchange with them for about $25 dollars per bottle. Warning, the 50 LB is the CO2 that is inside the bottle, but the whole thing weights way more than that, I am using a hand cart to transport the bottle to and from my pool shed, but you still have to handle the bottle and get it in and out of your vehicle. My local welding shop offers a pickup and delivery of about 20 dollars, so that might be in my future.

I have some questions for anybody interested in answering. And after reading on this site about a lot of issues with ORP, I am wondering if I am headed down a crazy path. Regardless, it does sound like the PH part of this setup will work pretty well, and a stable PH will be welcome. My main goal here is to stabilize the pool chemistry as much as possible and keep things balanced better. If the ORP ends up not working well, I might just switch the pump to a "timer" mode and adjust that instead to keep my FC pretty close.

Questions...

1.
I will be injecting CO2 into the pool return lines, but I have a few choices as to the location of such. Since I have an AA in floor cleaner, I was going to inject the CO2 at the last PVC elbow as the water leaves my pool shed on it's way to the sequencing valve for the cleaner, which is located closer to the actual pool. I am worried that the acidity of the carbonic acid might hurt the sequencing valve?? The other choice for adding the CO2 would be the return lines that are headed for the venturi skimmers (there are 2 skimmers fed with a 3/4 inch pvc line). These lines provide pressurized return water to the skimmer to create a high flow through the skimmer, and this water actually exits about a foot below the skimmers themselves.

Would I be risking damaging the sequencing valve (not sure if there are any metal components inside that thing), or would I better be served running the co2 through the skimmer venturis?? I am leaning towards the infloor system because the CO2 would have a lot greater time absorbing into solution going through all that apparatus, and also would exit the pool at floor level... I do know that the acidity of carbonic acid is pretty mild compared to muratic. Thoughts?

Same question with the liquid bleach? I can inject it at either location, but leaning towards injecting it at the skimmer venturis. I could also inject the bleach into the same line headed for the floor sequencing valves, but when CO2 is dispensing at the same time, would the low PH in that line damage or help the effect of the chlorine?

Currently, when I add chemicals of any kind, I simply slowly pour them into the skimmers while the pump is running at high speed, this dilutes them significantly as the flow rate through the skimmers is very high, and the water just exits out about a foot below the skimmer towards the center of the pool. And no, this water doesn't return to the pump as the skimmers don't connect to the pump inlets, so my equipment back at the shed doesn't see any water that doesn't return through the main floor drain.
​

2.
To be clear, my primary sanitizer is chlorine supplied as liquid bleach, however, I have an AA ozone system hooked up to the main filter pump. This is the pump that feeds the filter, and then the heater, and then the infloor cleaner and skimmer venturis (the heater is mostly bypassed 99% of the time anyway, we only throw that valve when we heat up the spa, which is rare). The way it is plumbed is a small tube sucks air through the ozone chamber and draws that through the pump impeller. There is a restrictor valve in this line so that the pump is limited in the amount of "ozone/air" that is being drawn into the impeller. What I am concerned with here is that I will be feeding water into the ORP sensor that has (in theory anyway) some ozone in it. Can anyone speculate as to how this will affect the setup of my desired ORP setpoint? I understand that there is no ORP value that is a standard, but rather I will have to adjust my pool chemistry to a desired setpoint, find the corresponding ORP value that registers, and then set that value as a target in the controller. However, the pump runs at different speeds throughout the day, and thus I would think is drawing in various different levels of ozone (in theory, again), and thus you would think the ORP value would then not be stable?? Perhaps I would be better served to just remove the ozone system completely as I'm not sure it's really doing anything to help??
​

3.
I would prefer that the injection of chemicals only happen when the pump is running at it's high speed times, which are for a few hours in the morning, and then again in the evening. However, other than a few early morning hours, when the pump isn't at a high speed I keep water trickling through the infloor cleaner at about 20% just to keep things from getting stagnant (and also to draw some of my theoretical ozone into the system;-) So, in the logic of the HL-CHEM system, is there a flow sensor in that testing orb? Or does Hayward use the logic in the Omnilogic to know when the pump is "ON" and thus safe to dispense chemicals. I don't want to inject chemicals when the system is just in a trickle state, but rather than when the infloor cleaner is running full blast and everything can get diluted out quickly. If there is a flow sensor in the HL-CHEM orb, I don't see it, and I'm not sure there is a threshold setting to dispense chemicals in the Omnilogic. I'm thinking I might decrease the run times on the infloor cleaner, but increase the flow rate for those times to compensate? Thoughts?? Also thought of wiring in a pressure switch to prevent the system from dispensing chemicals unless there was a certain pressure in the return lines. I saw a couple of adjustable pressure switches on Amazon that I could rig for this purpose.
​

In any case, I'm out to the shed to start the wiring of some outlets that will serve as the plug in spots for the Rolachem and CO2 solenoid. Bought a couple of LED nightlights that I will plug into the outlets so I can easily see when each system is "dispensing" chemicals. And I will try to post some pictures of all this and more when I get more into it.

I am hoping this project goes smoothly and the results are positive. After a lot of reading my hopes of the ORP working well is questioned.

Cheers to all,
Mark
 
CBC,

Thanks for the thread bump, but it's just crickets in here. I probably went a little overboard on my description and nobody want's to touch it. Doesn't matter anyway, I just figured it would be helpful to anybody else out there in the future trying to do the same thing.

My only questions would be
1. send the CO2 to the venturi skimmers or the in floor cleaner?
2. send the bleach to the venturi skimmers or the floor cleaner?
3. Is the "ozone" coming into my filter pump gonna throw off the ORP, and what should I do about it? Unplug it and throw it away, or adjust the ORP higher to compensate?

Cheers,
Mark
 
Sorry, you are asking questions about a system that very few have any experience with. (And the post was so long, admittedly I still have not read it all)

Generally seems that ORP sensors are not highly thought of (inaccuracy I outdoor pools with CYA) and I seem to recall that co2 injection was also not really recommended (I think because so much is required).
 
Update.

System is is in place and operating for 5 days now. What others have stated appears to be true. which is that in short the ph control works pretty well. While the orp Is a much more complicated situation.

I am am a bit miffed at Hayward because when I called them and discussed this in advance of purchase they led me to believe that I would be able to dispense chlorine automatically based on orp levels. This would be true for a salt pool. As the omnilogic panel can do that. But there is currently no logic built into their software to allow that control to a pump relay. Additionally. I was told that there was no requirement for a flow sensor as the logic of the system would know when the pump was already running and only dispense at that time. This is not true either.

So, my workaround was as follows. Instead of installing a flow sensor since I did not have one on hand. I took an old phone cord and cut off the end. Then twisted all the 4 wires together to short them together. This plugged into the flow sensor position thus fools the OmniLogic to constant flow. Just lie to OmniLogic and tell it there is a flow sensor in position 1.

Next, I created an "Interlink" rule that stated that neither the co2 nor the rolachem pump relays were allowed to operate unless the filter pump was "on", since I had bypassed an actual flow sensor.

I had had some problems ordering the correct CO2 system. I originally ordered the AC003 system but it turns out there is no gage or regulator with the AC 003 (stock internet photo is incorrect) so I sent that back and got the AC004, which has a bottle gage and an adjustable flow meter. This way I will know when the bottle is depleted, and I am able to set a flow rate.

The co2 system works so far really well. And I will try to report back later on how long the 50lb cylinder lasts. The system cycles the relay in what appears to be time intervals relative to the difference between actual ph and ph set point. I was using about a gallon and a half of 30 baume acid a week previously. So we will see.

To get around the Omnilogics lack of orp to relay control, things are a bit more messy. What I have done is to lie in the setup menus and tell the OmniLogic that I have a salt cell installed. That enables the display of orp levels in both the app as well as the html versions of control. I was getting a flow error that was annoying until I realized if I turn "off" the salt cell the error goes away and I am still able to view the actual orp voltage. So in short I can see what the orp value is, but the OmniLogic doesn't dispense based on that value.

Instead, I am simply running the rolachem pump twice in the evening at about sundown for a preset amount of time. Which is adding about 2/3 gallon of bleach daily. The "interlink" rule only allows the rolachem pump to work if the filter pump is on, and at that time of night the pump is already running. The rolachem is a 12 GPD pump it takes about 80 minutes to pump that bleach into the pool. I will have to adjust those times or manually override based on orp and test results.

As to the question of ozone... I had originally thought that my ozone would throw off the orp values. But so far, turning on and off the ozone there doesn't seem to be much change in orp. Still need to play with that some. Who even knows if the ozone system is working. It just has a light on it, so the system could be out and who would know.

So far, it appears that 760 mv is something relative ly close to 4 ppm chlorine. But keep in mind that orp values change via a whole matrix of variables. So your values might be different.

Last night my numbers were as follows. Taken at sunset before the chlorine was added... This was after 4 days of not manually adding anything.

ph 7.5
fc 2.0
cc 0
ch 225
ta 80
cya 30
borates 40
water temp 92
orp 740

i think I need to get the cya up to closer to 50. As pool is full sun. Which I will do with trichlor tablets slowly in a feeder. I used those on occasion when out of town.

The the other thing that irritated me was that the Hayward test cell is made of clear plastic and then the sensors are 1/2 inch pipe thread. Putting excessive tape on the treads will crack the plastic orb, but the thing is tricky to get to seal. 10 attempts to retake things and it's still leaking at higher pump speeds. Even though I have throttled the input valve down significantly. I might switch to thicker pfte tape. Even the pre installed plug in the orb was leaking.

So, Hayward, if you are listening. Please update your OmniLogic software to allow for ORP control to a relay, and please redesign that test cell and make it more sturdy so we can get a good seal. Also, remove the requirement for a flow switch in your logic. Even better, an adjustable pressure switch would work better for this type of application so we could eliminate dispense of co2 at low pump speeds, as without adequate flow I doubt that co2 is going to bubble into solution.

Any comments appreciated. I hope I have helped somebody out there in my description and setup. If I can do something better with my system, somebody clue me in.

Cheers,
Mark
 
So, after a few weeks now everything working pretty well. My fc is holding between 3 to 4 measured in the morning. And the bleach is injected at night. I have been putting some muratic acid into the pool when it is convenient to do that and it is prolonging my CO2 bottle and keeping my TA from climbing.

I ran ran a homemade pool chiller the other night. Which is just a 2 inch pic pipe with a jillion tiny holes that screws into a bubbler on my wading shelf. It cools the water about 5 degrees per night but also raises the ph and lowers the TA. So rather that dump a bunch of CO2 chasing that I just threw in some acid. Figured I would take the opportunity to lower the TA. I add the acid with a tall pipe fitted with an end cap. The end cap has a tiny hole drilled into it. I stand the pipe into the Venturi skimmer and pour in the acid. The acid slowly gets added to the skimmer flow and gets diluted pretty well. Don't do this with a non Venturi skimmer as the flow would take the acid straight back to the pumps and equipment.

So this way the CO2 doesn't get all used up, and I have it in reserve to hold the ph at 7.7 when we neglect the pool otherwise.

The other thing I have been tracking is the relationship between orp and ph. Since I had dropped the ph down significantly, I noticed the ORP shot up significantly. Which concurs with others statements that ph must be held steady to use the ORP value as reliable.

So so with my 6 gallon bucket of bleach and the co2 bottle. I can easily go a whole week and not have to mess with chemicals. That was my goal in addition to making the pool more immune to neglect when we get busy and distracted doing other things or traveling.

Life is is good!

oh, found a scorpion tonight that attempted suicide by jumping into the skimmer basket as I was pulling the basket to clean. Had to then reach my hand back down there in the dark to finish the job. So I find the scorpion and he jumps out of the wet leaves and back into the skimmer. Gets sucked into the Venturi and out into the pool. Then had to turn on the pool lights and fish him out with a net. He was still plenty alive after several minutes being submerged. Will just say he perished regardless. No reason to swim with that fellow around... Those buggers are nasty....
 
In response to BDAVIS466


Good advice. Although I am learning that the ORP moves around pretty wildly for other things too. Perhaps my approach of 2/3 gallon of 10% bleach on a timer is about as good as I can do. Still have to test the pool regularly anyway.
 
Last edited:
Still adapting my routine to the new setup, but what seems to work well for me so far is to use a little acid when I'm at home and drop the ph into low 7's, and then let it drift up to 7.7 when I'm not home. The CO2 kicks in then and prevents it from getting too high. This combo also seems to be keeping the TA between 70 and 80. This has also prolonged the CO2 bottle, as there isn't any easy way to know how much CO2 is left until the gage pressure rapidly drops to zero. Roughly 3 weeks and still on first 50 lb bottle.

As as for ORP, the pool is staying right on 3 to 4 ppm FC with its daily dose of about 2/3 gallon of bleach. The ORP shifts high when the ph drops, and low when the PH climbs, even though the FC is fairly steady. So using actual ORP controller would be very erratic if you didn't have a very stable ph. But I'm getting a feel for what ORP is normal for a particular ph.

I've been running an aerator chiller spray pipe thing which really drives the ph up, so didn't want to use up all my CO2 while I'm home and it's easy to add acid. 93 degree water isn't that refreshing. The chiller drops it nicely into the high 80 range overnight.

In Any case I must say the best part is that I can view the ph and ORP when I'm on the road. Just open my app a few times a day and I can see the pool trending and make sure the ph isn't getting high. At some point the bottle will run out and when the ph doesn't stop at 7.7 I'll get an additional warning of a ph feed timeout. Time to change the bottle then.

Refill my bleach bucket a few times a week and that is painless. Wondering though if my clear tubing is a good choice as the suction side almost looks like it's cavitated to a vacuum? Thinking of changing that to some reinforced tube for rigidity. But for now the bleach is getting where it needs to go and at the right rate.

So so while it's not really automated, I'm not having to constantly test and mess with it.
 

Enjoying this content?

Support TFP with a donation.

Give Support
Hmm, you're using a liquid feeder for chlorine? Or do you do it manually? I'm planning on utilizing the salt generator. However I've noticed in the hayward catalog an adapter for an automated liquid chlorine feeder.

Sent from my ONE A2005 using Tapatalk
 
Sorry for the late reply. Have not logged on here for a while.

Yes, using a Rolachem pump that pumps in liquid bleach daily (starting about 9PM). I have varied the time somewhat here to keep the FC at my desired level. I am keeping my FC around 3 to 4 now, higher than I previously was doing, after an algae bloom earlier this year rocked my pool pretty hard. Never want to do that again. With the automatic adding of chlorine every day I haven't had any issues at all. I can still dump a bit extra bleach into the pool is it gets used hard or if my CC test gets a bit pink.

Yes, Hayward was about to release a liquid chlorine feeder when I talked to them about my setup, it is very similar to their liquid acid feeder that they market as well.

The problem is that the Hayward Omnilogic doesn't have a way to trigger the relay for a chemical pump like that based on ORP value. But if you have a salt cell I'm pretty sure the ORP can trigger the salt cell to work. You best call Hayward directly and get that answered though. Perhaps they have updated their software again in the last few months, but I haven't checked.

What IS working exceptionally well is the PH control with the CO2 bottle. I add a little acid still when it's convenient for me just to prolong my CO2 bottle and keep my TA from getting too high, but it's been almost 3 months and I'm still running off of my original 50 pounds of CO2.

You should know that the ORP is pretty stable when the PH is stable, but for example, if I put in excess acid and drop the PH down in the low 7's (from my current setting of 7.7) , the ORP swings a good 100 to 150 mv.

In a nutshell my setup is a LOT easier to deal with now that things are more stable, and the automation, although not perfect, is certainly the main driver there. And I should say in addition to a wealth of knowledge coming from this site thanks to others.

Hope this helps.
Mark
 
Last edited:
That's very useful to know, I'm still a bit hesitant to order the Omnilogic seeing as it's still very buggy from the app and home automation side of things. (along with the inability to control network lights)

My question for you is why did you go with co2 vs the acid feed?

Sent from my ONE A2005 using Tapatalk
 
I am still pretty new here, but I can say that I had to completely ditch the ORP setting/sensor on my Intellichem when it came to it dosing chlorine. Too many times did I come home to my SWG on 100% when my FC was well over 12, but the ORP was in the low 600s. Whether it was the SWG, sunlight, or CYA level, it was not a good situation so now my Intellichem is in charge of MA and MA only :)
 
I went with the co2 for a couple of reasons. The 50 lb bottle means a larger reservoir and less touches. The mechanism for injection is easier to setup and maintain, and there is no nastiness or corrosion issues to deal with. I did not want to keep, store, or have acid in my pump house due to fumes or accident potential. Same with chlorine or even bleach.

All those chemicals are are stored in a cedar "chemical locker" that sits outside my pump house. Including the bleach reservoir (using a 6 gallon bucket that my boric acid came in, cause has a sealed lid) for the rolachem pump. But the co2 tank and all the mechanical items are inside the pump house. Just a warning on the co2 in an unvented area could take you down if you had an excessive leak. So ventilation is a must just in case.

The 50 lb bottle when full is REALLY heavy though. So you need to be prepared for that. However I'm still on my first tank after several months now. I have been using some acid when I'm around and it's convenient because I don't want the TA getting too high, and especially if I'm trying to cool the pool with a sprayer hooked to a jet, which will raise the PH fast.

Just got back from a 2 week absence and hadn't touched the pool entire time except our house sitter cleans the skimmers. The in floor cleaner works awesome. Not a speck of anything in the pool and the water is crystal clear.

Ph 7.5
FC 7.5 (rainy and cloudy last several days)
CC 0
TA 60
CH 275
CYA 50 (I used about 8 pucks total to extend the smallish bleach container this summer various absences)
Borates 40 or 50. Hard to tell with the strips.

I couldnt be happier.

20 gallons of bleach from Walmart yesterday. Usual questions about who I had killed. I always respond "nobody yet".

Pool temperature down to 84 last night and nobody would get in, so I fired the spa up a bit and we did that instead. The disadvantage of warm water temps is we all get spoiled so fast. Sunny today and yard work will have us in there tonight I'm sure. Grillin up some green chili burgers��
 
Update...

Yesterday I went out to the pool shed to check things out. Normally I had about 900 PSI on the CO2 gage on the Hayward regulator, but that number was down to about 400. Since the CO2 bottle is filled mostly with liquid, and gasses off to the top, I knew that the liquid had run out and I was down to just 400 PSI of gaseous CO2, so I headed to my local air distributor and got a new bottle.

2 things to note.

1. I have said this before, but dang that bottle is heavy. I have to tip it up onto my tailgate and then get under it and shove. It's gotta be in the range of 200 pounds empty. Then the new one has an additional 50 pounds of CO2 in it. Dang. Otherwise it's a snap to change out. Maybe 5 minutes?

2. 25 dollars total out the door for a replacement bottle. When you buy your CO2 bottle ask for a "slick neck" bottle. What this means is that you have a bottle that isn't owned by a particular company, so you can trade it in for a new bottle anywhere. Ask when you change out for a replacement bottle that is "slick neck", which keeps your options open as to where and how it's filled again. If you take a "Praxair" bottle to a non "praxair" place, they might not be able to mess with it, and vice versa.

So I think I got close to 4 months of service with 25 dollars worth of CO2. Of course you need to add the other costs of operation up. Regulator, probe, controller, installation, and hassle factor of handling the cylinder. But my ph sits at exactly 7.5 ALL the time, which stabilizes everything so nicely. My opinion well worth it.
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply