I think the purpose of IntelliChem is so that you don't (in theory) have to test and add chemicals to manage pH and Chlorine daily, and rely on those things being automated. The claim is not that you don't have to test at all; you still need to keep TA, CYA (if used) and CH at levels that prevent scaling / corrosion.
New pool finished about a month ago; could I have some help please...
- Thread starter Nezil
- Start date
So I tested my pool water and tap water today with the K-2006 kit to get some readings, and here they are:
For reference, IntelliChem reported a pH of 7.62 and an ORP of 700 when the last reading was taken at about 4pm. I took my measurements at 7pm; 3 hours later.
If you've been following the news, you'll know that California just went through some of the heaviest rains since records began. San Diego was spared the brunt of the storms, but I did have to drain 2 or 3 inches from the surface over the last two weeks, and an inch or so before that.
Does this seem reasonable thus far? I don't have the calculations for CSI, but LSI would suggest that the water is currently mildly corrosive. Sanitisation aside, would it be advised to add some Calcium at this point to reduce the saturation index a little?
For reference, IntelliChem reported a pH of 7.62 and an ORP of 700 when the last reading was taken at about 4pm. I took my measurements at 7pm; 3 hours later.
- pH: 7.6
- Free Chlorine: 0.8
- Combined Chlorine: 0.0
- Total Alkalinity: 80
- Calcium Hardness: 190
- Cyanuric Acid: 0.0
- Water temperature: 55F
- Total Alkalinity: 130
- Calcium Hardness: 200
If you've been following the news, you'll know that California just went through some of the heaviest rains since records began. San Diego was spared the brunt of the storms, but I did have to drain 2 or 3 inches from the surface over the last two weeks, and an inch or so before that.
Does this seem reasonable thus far? I don't have the calculations for CSI, but LSI would suggest that the water is currently mildly corrosive. Sanitisation aside, would it be advised to add some Calcium at this point to reduce the saturation index a little?
- Jul 21, 2013
- 52,451
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
We never recommend a FC of 0.8. It can let algae take hold.
Get your FC up by the time your pool water begins warming.
See FC/CYA Levels
Get your FC up by the time your pool water begins warming.
See FC/CYA Levels
So I have some updates everyone... My pool builder suggested that I didn't need to worry about CYA, but that seems like dumb advice. I watched the speed that Chlorine and ORP levels dropped without CYA, and it was pretty surprising, even in winter as it is now.
During the first few weeks, I'd add liquid Chlorine about once / week, but it would effectively be zero within a couple of days. As you all know, when I started adding salt to my pool, the SWG was having a tough time generating Chlorine to keep up with the loss during the day. I do think this was partially caused by a low salt level because I was slowly bringing it up to where it needs to be (it's at 3200 ppm now according to the Taylor test kit), and partially caused by the sun burning off what Chlorine could be generated... hence the 0.8 level I quoted last Wednesday.
Starting on Thursday, I added 4 lb of CYA in granular form. I put this in a sock in the skimmer, and after 24 hours squeezing it felt like there was only a paste in the sock; no granules. At this point I pulled the socks out, and slowly mixed the paste with buckets of pool water and poured the 'milk' down the skimmer. As you would expect, this resulted in a low pH initially, but by Saturday afternoon, I was getting just under 30 ppm CYA result with the Taylor test kit. Pool Math suggests that for my 18,000 G pool, I'll need 4lb 4oz to get to 30 ppm, and that after adding 4lb, I should be at 26.5 ppm, so this all does check out.
Anyhow, during all of this, the ORP reading obviously went low due to the CYA getting dissolved, and it's slowly recovering. The result of this is that the IntelliChem requested full Chlorine generation to try and raise ORP, and this took me from 1.2 ppm Free Chlorine on Friday night, to 6.4 ppm Free Chlorine by Sunday morning. The pool pump and SWG were only on from 7am - 4pm, so that's a lot of chlorine to be generated in such a short duration and in cold weather... good to see!
I've been monitoring the Free Chlorine level since then, letting it drop to < 4 ppm with no SWG and I'm seeing a drop of about 1.5 ppm every 24 hours. This is a lot lot slower than with no CYA. I think it would have been gone already if that had been the case.
I'm impressed that CYA works so well, and after such a short period of time.
ORP is still < 700 even though Free Chlorine is so high, but it's rising. I'm hoping that it will stabilise soon and I'll be able to find an ORP value that correlates with Free Chlorine for my pool.
Next step is to bring the Calcium Hardness up to a target of 300ppm.
During the first few weeks, I'd add liquid Chlorine about once / week, but it would effectively be zero within a couple of days. As you all know, when I started adding salt to my pool, the SWG was having a tough time generating Chlorine to keep up with the loss during the day. I do think this was partially caused by a low salt level because I was slowly bringing it up to where it needs to be (it's at 3200 ppm now according to the Taylor test kit), and partially caused by the sun burning off what Chlorine could be generated... hence the 0.8 level I quoted last Wednesday.
Starting on Thursday, I added 4 lb of CYA in granular form. I put this in a sock in the skimmer, and after 24 hours squeezing it felt like there was only a paste in the sock; no granules. At this point I pulled the socks out, and slowly mixed the paste with buckets of pool water and poured the 'milk' down the skimmer. As you would expect, this resulted in a low pH initially, but by Saturday afternoon, I was getting just under 30 ppm CYA result with the Taylor test kit. Pool Math suggests that for my 18,000 G pool, I'll need 4lb 4oz to get to 30 ppm, and that after adding 4lb, I should be at 26.5 ppm, so this all does check out.
Anyhow, during all of this, the ORP reading obviously went low due to the CYA getting dissolved, and it's slowly recovering. The result of this is that the IntelliChem requested full Chlorine generation to try and raise ORP, and this took me from 1.2 ppm Free Chlorine on Friday night, to 6.4 ppm Free Chlorine by Sunday morning. The pool pump and SWG were only on from 7am - 4pm, so that's a lot of chlorine to be generated in such a short duration and in cold weather... good to see!
I've been monitoring the Free Chlorine level since then, letting it drop to < 4 ppm with no SWG and I'm seeing a drop of about 1.5 ppm every 24 hours. This is a lot lot slower than with no CYA. I think it would have been gone already if that had been the case.
I'm impressed that CYA works so well, and after such a short period of time.
ORP is still < 700 even though Free Chlorine is so high, but it's rising. I'm hoping that it will stabilise soon and I'll be able to find an ORP value that correlates with Free Chlorine for my pool.
Next step is to bring the Calcium Hardness up to a target of 300ppm.
Calcium will go up over time as water evaporates and you add more tap water. The calcium stays in the water.
That said, I get plenty of rain dilution here and so I keep my calcium in the 500’s.
If you have to use LC on a regular basis (when your SWCG is offline), it is best to add a little every day. When I was using LC exclusively (before SWCG), I would add a pint to a quart every day. This keeps your FC at a more consistent level.
If you have to add LC in one dump, such as going on vacation, then add more LC and let it drift down but never going below your target minimum. You can add LC up to the SLAM level for your CYA without concern.
For future consideration if needed.
- Jun 24, 2021
- 7,500
- Pool Size
- 30000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60
Problem is that an ORP sensor does not know how much CL is bound with CYA that can be freed as needed. So an ORP system with high CYA will think that CL is low when it is not. An ORP system cannot work as designed with high CYA levels. From experience here, if CYA is over 30 ppm, then the ORP will not change in a meaningful way even with very large changes in FC. Below 30 ppm, ORP is usable for regulating FC.
Couple useful links...
We don't recommend ORP
By the by, we don't recommend any brand of ORP based control for outdoor residential pool. Hi Jason, I've seen you say that a few times already, but I have not been able to find a good thread on why. I would like to read why you make that recommendation. Can you point me in the right direction?
www.troublefreepool.com
CYA level when running SWG and ORP probe
Looking at having a pool installed in early 2018. I have been reading up on TFP forums as much as possible to gain valuable insight to running a pool (will be 1st time owner)... So far the forums have been a goldmine of information...:thumleft: One thing that has been a little confusing is the...
www.troublefreepool.com
My CYA level is < 30 ppm; 26.5 ppm if I had to guess based on how much was added and the size of my pool. I do think that sensor may have gotten saturated with CYA during the initial dosing in to the skimmer. CYA is known to take a long time to dissolve, and dumping it in the skimmer makes in settle in the filter and dissolve from that location. The feed to the probe is after the filter, so during this dissolving process, the probe is hit with a CYA level that isn't actually representative of the whole body of water in the pool. I therefore don't expect an accurate ORP reading for up to a week, because CYA is probably still dissolving in the filter.
After a week however, I'd hope to see ORP readings that align more closely with Chlorine readings.
I am at this point planning to move control of the SWG over to manual (percentage + time control) whilst correlating ORP readings with FC manual tests. If I start to see a correlation, I may try ORP control again, and if I see stability from the manual approach... maybe I won't bother. For the time being though, I'm going to keep my CYA below 30 ppm so that I can at least monitor the ORP reading. We're months away from being able to swim in the pool anyway, and I'll probably use this year to experiment with the system.
Pentair recommends < 30 ppm CYA, but also recommends CYA for outdoor pools, so I'm going to try with 30 ppm. Worst case is ORP will be low and I'll be stressing the SWG un-necessarily. From what I've seen so far though, the IC40 I have for my 18,000 Gallon pool has got plenty of capacity, so it's only lifetime that will suffer.
- Jun 24, 2021
- 7,500
- Pool Size
- 30000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60
Great plan. Yeah, for cell life, I'd run in on % + time and not bother with ORP. Just me I guess. I don't have automation, and I know the percent to run each month of the year here in Ohio...and FC stays super steady.
Here is a brief update...
The recent cold snap has meant that the SWG is right on the border of being able to operate. Water temperature doesn't fluctuate as much as air temperature of course, but I'm finding that the SWG doesn't operate at night, but does most of the time in the day. This is making it a bit more difficult to correlate FC to ORP. Having said that, I am seeing a pretty consistent drop of just under 1 ppm of FC through the day, based on Turner manual measurements, and I also see a drop of ORP between the period when the pump is running overnight, stopping at 6am, and when it starts up again at 12.00pm.
My current weekday schedule is
This schedule is based around avoiding the peak electricity rate (51¢ / kWh) from 4pm - 9pm, and making best use of the super off-peak rate (15¢ / kWh) which runs from midnight to 6am on weekdays, and midnight to 2pm on weekends and holidays. San Diego has the highest electricity prices in the country, and they go higher still in the summer months (82¢ / kWh peak!!!). Once the weather and pool water temperature increases, I plan to switch to a daytime schedule to produce chlorine as well as filter and move water more during the day. I also have more solar PV being installed this weekend to try to offset some of this extra usage!
I've only lived in San Diego for 13 months so far, but I don't remember it being this cold last year!
The recent cold snap has meant that the SWG is right on the border of being able to operate. Water temperature doesn't fluctuate as much as air temperature of course, but I'm finding that the SWG doesn't operate at night, but does most of the time in the day. This is making it a bit more difficult to correlate FC to ORP. Having said that, I am seeing a pretty consistent drop of just under 1 ppm of FC through the day, based on Turner manual measurements, and I also see a drop of ORP between the period when the pump is running overnight, stopping at 6am, and when it starts up again at 12.00pm.
My current weekday schedule is
- 1am - 5am pool (with SWG)
- 5am - 6am spillway
- 12pm - 3pm pool (with SWG)
- 3pm - 4pm spillway
- 7am - 8am spillway
- 8am - 3pm pool (with SWG)
- 3pm - 4pm spillway
This schedule is based around avoiding the peak electricity rate (51¢ / kWh) from 4pm - 9pm, and making best use of the super off-peak rate (15¢ / kWh) which runs from midnight to 6am on weekdays, and midnight to 2pm on weekends and holidays. San Diego has the highest electricity prices in the country, and they go higher still in the summer months (82¢ / kWh peak!!!). Once the weather and pool water temperature increases, I plan to switch to a daytime schedule to produce chlorine as well as filter and move water more during the day. I also have more solar PV being installed this weekend to try to offset some of this extra usage!
I've only lived in San Diego for 13 months so far, but I don't remember it being this cold last year!