New SWG install - late in the season

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J

JasonBigCountry

Active member
Jun 21, 2022
40
Abilene, Texas
Pool Size
20000
Surface
Vinyl
Chlorine
Liquid Chlorine
Hi folks,
I've been considering SWG for the last six months or so (initially caused by some high liquid chlorine prices I saw pre-season, which then corrected by the time I was ready to open the pool). Finally, I pulled the trigger last night.

Why?
[Background info]
Because my chlorine dosing pump (Hanna Instruments BL101) started giving me bigger problems than usual. I'm generally fairly happy with it, but it seems to require a bit more fiddling than I expected:
  • I have to replace the peristaltic pump tubing more often than expected (not too bad of an expense once I found a tubing that worked that was available in bulk, but still an annoyance when it starts leaking, or can't get chlorine to flow).
  • Still have to lug jugs to fill the tank.
  • Sometimes the tubing starts to leak around fittings, and I have to re-do the connections (and clean up the salt residue left over)
  • Occasional bleach stains on clothes when I'm not careful enough (Ok! Not the BL101's fault, but a still factor in my decision!)
  • Most pressingly, sometimes the ORP probe seems to lose it's mind, reads very low, and the pump just pumps all available chlorine into the pool. This has only happened twice, but it's very annoying when it happens. The first time, I thought it was due to an additive I'd recently put in the pool, but not sure. The second time.... No idea.
The second time was a few days ago. Over the course of three days, it pumped seven gallons of bleach into the pool, raising the FC PPM to 19 (when I realized something was wrong and checked.) I should have checked when it 'drank' the first four gallons, but I'd lost track of when I added that, and just figured it had been hot lately, and my CYA must be getting low. I added three gallons, and it 'drank' most of that in 6 hours, and my ORP was still reading in the 500's (I usually keep it set to 700). I checked FC, and saw 19.

I went through the process of checking the sensor with calibration solution, cleaning it, checking all pool water variables, dialed in pH (it was a bit high) and re-checking/cleaning and finally calibrating the sensor the next day, only to still have it reading very low while FC was still too high at 16ppm.

I figured my sensor probe may be shot, so sent a mail to Hanna. They responded quickly (I've really liked their responsiveness!) and helpfully suggested the probe may be worn out - they last 12-18 months. They cost $169.

Hm...
I was pretty sure I wanted to SWG anyway, had just figured I'd wait till next year, but this sped things up.
[End of background info]

So, I already had an idea I wanted one of the circupools, having done some research about a year ago, so I consulted my notes, and spent a couple hours reading here last night, and finally ordered a RJ-60 Plus from DSP. I have a 20k pool. Based on the general advice of 'go 2x', plus some posts I read about SWG in hot climates like Las Vegas, and my own experience with how fast the chlorine can be consumed even when all is 'good', I figured I wouldn't be sad with the 3x approach. It's rated to produce 3.1lbs per day, and I rarely have to add more that one gallon of 10% liquid per day, which I'm figuring is about .8 lb (not sure that works, but I'm assuming a jug of weighs about the same as water, 8lb/gallon and that the 10% is by mass.. Anyway, I figure I'm in the ballpark.). So, I'm figuring I should/may be able to run at 25% and in good shape.

So, besides bragging :), I'm writing to ask a couple questions about what I should expect.

  1. Power consumption: Looks like these things consume about 200-300 watts when running from a few posts I read here. Can anyone provide specific measured values (via kill-a-watt, or similar)? I'm curious what this will do to my electric bill though I expect it will be way cheaper than the 100-200 I spend on bleach
  2. Salt - I'm looking for a good salt to start with. I saw a few 'scary' posts here about Clorox and ... some other brand I forget. Mortons? I'll need ~600lbs, I think.
    1. Anyone have good or bad experience with the Pool Time brand from Home Depot? Says it's 'pure' and dissolves quickly.
    2. What about the Sure Soft at Lowe's?
    3. Any other you've been happy with that are fine grains / fast-dissolving and won't make a mess/contain a bunch of Crud?
  3. Oh, and it looks like the consensus for salt testing is the Taylor kit. Any others have another favored choice?
Thanks!
I'll follow up with any other install questions if I have any. I intend to wire it up with my home-grown pump controller so that it's on whenever the pump is on (I have a manual 2-speed pump that I've converted to be automated via a raspberry pi and some relays, etc.)
 
Jason,

I run my 3 HP IntelliFlo VS pump and SWCG 24/7 and that costs me less than $20 bucks a month..

It appears you have a single speed pump.. If so, that is where all the electrical costs will come from.

You will need to run the pump long enough for your cell to generate the amount of chlorine your pool uses each day.

The good news is that you bought a large cell.. This means you can set the cell's output to say 80 or 90% and that will allow you to run the pump for the shortest amount of time possible.

We also recommend that the CYA of saltwater pools be kept at about 70 ppm. This will help reduce the amount of FC that is consumed by the sun.

Since you have been using Liquid Chlorine, you might be surprised at how salty your pool water already is.. Make sure you test it before you add any salt.

Pretty much, any salt that is not Clorox, is ok to use.

Thanks,

Jim R.
 
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Awesome - thanks for the quick reply!

I actually have a 2 speed pump though it is 'dumb', not a fancy VS! I kinda look forward to installing a VS one day - sounds like they're way more energy efficient than mine, even on the LOW setting.
My pump runs more or less 24/7. Most of the time it's on low (~250 watts), but it kicks up to high a few times per day for 30 minutes or so, and on demand when I want to run a vacuum, or see a lot of bugs on the surface, etc.

I have to run it a lot because we have so many insects that land in the pool and die that it gets disgusting pretty quick if I don't keep it on. I could possibly shut if off for a few hours each night when the bugs settle down, but I've left it on since the current dosing pump wasn't wired to turn off with the pump. (Mind you, the water stays pretty clear, I just mean all the floating dead bugs gets disgusting.)

I'm hoping the SWG draw is tiddly. Maybe 250 watts. If so, and it only has to run, say, 6 hours per day, the additional cost will be negligible.

Thanks for the heads up on the current saltiness. I'll order the test kit now, so I'm not left wondering at a crucial moment.
 
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Follow up to my first post above:

I forgot to mention in my [Background info] section that this morning the ORP was reading 757-758... sigh. If that had happened before I placed the SWG order, I'd have probably delayed another year, but I plan to just go ahead.

I have no idea if I can trust that value, seeing as nothing had been done to the pool since yesterday afternoon, when the ORP was reading 685 and the FC was 16ppm. It's frustrating. Maybe it's working fine now, but even so, I'd probably need to recalibrate it since it started reading differently.

I realize that ORP is a measure of sanitizing potential, and not just some analog of FC, and as such it can be influenced by other things, but I think something is getting flaky here, and I just don't want the headache anymore.

Oh! By the way, a follow-on question about maintaining SWG:

My wife asked, "Are you going to need a new sensor to measure the chlorine level [with the SWG]?"

I told her "No, I think what folks do is just install it, set it to a level, and then check the chlorine level daily until they get the production level set to something they're happy with, and then leave it alone. Then they just check FC weekly [along with other routine tests] and make adjustments as needed. Since the chlorine produced is so cheap free, they're not too worried about a slight over production."

Is that a fair assessment of how most SWG owners operate?

Thanks
 
Jason,

SWCGs and ORP systems do not work well together unless the CYA is at 30 or below.. Running a CYA of 30 does not make sense when using a SWCG..

ORP is not something we recommend. But... it is your pool and you can run it anyway you want.. :mrgreen:

Pump wise, your 2-speed pump should close the SWCG's flow switch on low. But the only way to know for sure is to install the SWCG.. :( If you have a heater or other stuff in the return flow path it may or may not work..

Just to make sure you are aware... In the Winter, when the pool water temp falls below about 52 degrees or so, the cell will no longer make chlorine.. You will have to switch back to Liquid Chlorine or tablets.. For me this is usually about 2 or 3 months and the pool does not use much FC then anyway..

Thanks,

Jim R.
 
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Thanks for the info.
In my case, the ORP sensor is part of the BL101, and I'll be pulling that out (or disabling it at least) once I install the SWG.

I'm not sure what I'm going to do about winter. This is only my third winter with this (AG) pool. The last two times I closed it and put a cover on it. Good chance I'll do that again, around November. OTOH, closing and reopening is a bit of a PITA, and if I can keep it running year round, maybe I will.

We get freezing temps here, sometimes for days at a time, but I'm also thinking if I can keep the water circulating, it would be ok. The question is the "if". What if I get a power outage? :)
 
Jason,

That happened here in the DFW area and we had a massive number of pools damaged. :(

Almost no one in this area closes their pools. But low temps combined with loss of power for several days did a lot of people in.

I was lucky, but a lot of people were not.. Frozen pipes, filters and pumps...

Thanks,

Jim R.
 

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JasonBigCountry said:
Oh, and it looks like the consensus for salt testing is the Taylor kit. Any others have another favored choice?
Click to expand...
I’ve got an Extech EC400 in addition to the K-1766. It stays within 100-200 ppm of the Taylor kit. It’s fast convenient and my default go to, but I wouldn’t have one without the Taylor as a backup just in case I come across something weird and I need a “sanity check”.
 
Jason,

I am glad to see that you have the smart-stir.. :goodjob:

I have the Taylor K-1766 salt test kit, but in my opinion it is almost useless without the speed-stir..

When you use the speed-stir it will give you repeatable and accurate salt readings every time.

Without the speed-stir it is much harder to use.. Maybe it is because I can't swirl, count drops and watch the color change, all at the same time... :mrgreen:

Thanks,

Jim R.
 
Jimrahbe said:
Without the speed-stir it is much harder to use.. Maybe it is because I can't swirl, count drops and watch the color change, all at the same time... :mrgreen:
Click to expand...
Without a speed stir you need 4 hands, 6 eyes, and 2 brains…and the results are still questionable. With a speed stir you need a beverage, half a hand and a modicum of sobriety. It’s an easy decision to pull the trigger on a speed stir. 😂
 
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Answering the OP's question about the power drawn by RJ-60... To monitor the SWCG, I installed a current transducer in the electrical subpanel and added code to my pool controller to measure and chart the current:

Screenshot 2024-08-14 204017.png

In the diagram, RJ-60 was turned on at 8am and off at 8pm. The duty cycle (SWCG power) is set to 65%.
During active time the current is about 0.7A, and when resting - about 50mA. The average power drawn by the RJ-60 is then:

0.7 [A] * 240 [V] * 0.65 + 0.05 [A] * 240 [V] * 0.35 = 109.2 [W] + 4.2 [W] = 113.4 [W]

The downward peaks seen in the diagram show times when RJ-60 switched current direction. From my observations so far, this always happens during active time and it's pretty much random.

There will be more details coming soon, with some surprises, but nothing really serious. I still like my RJ-60.
 
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pjt said:
So small you won't notice it.


Diamond Crystal Solar Naturals (blue bag). Sold at Home Depot, Ace, etc..


The K-1766 is the gold standard for homeowner salt testing.
Click to expand...
Thanks for the info - I ordered the K-1766 from Amazon yesterday with hopes that it gets here before the SWCG!

Lake Placid said:
I’ve got an Extech EC400 in addition to the K-1766. It stays within 100-200 ppm of the Taylor kit. It’s fast convenient and my default go to, but I wouldn’t have one without the Taylor as a backup just in case I come across something weird and I need a “sanity check”.
Click to expand...
Right! I had a similar thought when placing the order - I saw an electronic tester for less money than the K1766, but decided I wouldn't trust it without validating against something like the Taylor kit.

Lake Placid said:
Without a speed stir you need 4 hands, 6 eyes, and 2 brains…and the results are still questionable. With a speed stir you need a beverage, half a hand and a modicum of sobriety. It’s an easy decision to pull the trigger on a speed stir. 😂
Click to expand...

I concur - but will add "decent light" to the requirements... I recall one time I was measuring at twilight and got some squirrelly results. Now I do it in full daylight (or inside if I have to measure something after/near sunset)

hexabc said:
Answering the OP's question about the power drawn by RJ-60... To monitor the SWCG, I installed a current transducer in the electrical subpanel and added code to my pool controller to measure and chart the current:

View attachment 604342

In the diagram, RJ-60 was turned on at 8am and off at 8pm. The duty cycle (SWCG power) is set to 65%.
During active time the current is about 0.7A, and when resting - about 50mA. The average power drawn by the RJ-60 is then:

0.7 [A] * 240 [V] * 0.65 + 0.05 [A] * 240 [V] * 0.35 = 109.2 [W] + 4.2 [W] = 103.4 [W]

The downward peaks seen in the diagram show times when RJ-60 switched current direction. From my observations so far, this always happens during active time and it's pretty much random.

There will be more details coming soon, with some surprises, but nothing really serious. I still like my RJ-60.
Click to expand...
Perfect :) And nice setup! I monitor my usage on a coarser level by running all the equipment through a circuit monitored by my Emporia Vue 2.

So, sounds like this thing will be cheap as chips to run. I'm not sure where the 109.2W + 4.2W = 103.4W came from, but I assume you're trying to exclude some current that you've noticed is a baseline in your measurements, or something like that. In my case, I'm most interested in the .7 * 240VAC, or 168W peak. I'll see what my own duty cycle is when I get it set up. Do you use the RJ-60 to manage the duty cycle, or does your controller handle that externally? I'm guessing your controller turns it on from about 8am and off at 8pm from the graph, and the Rj-60 handles the 65% during that window. It also appears to run its duty cycle on a three hour period. Might be good to know that so that I can plan around that if I schedule its on/off times, too.

This should be fun :)
 
JasonBigCountry said:
I'm not sure where the 109.2W + 4.2W = 103.4W came from, but I assume you're trying to exclude some current that you've noticed is a baseline in your measurements, or something like that. In my case, I'm most interested in the .7 * 240VAC, or 168W peak. I'll see what my own duty cycle is when I get it set up. Do you use the RJ-60 to manage the duty cycle, or does your controller handle that externally? I'm guessing your controller turns it on from about 8am and off at 8pm from the graph, and the Rj-60 handles the 65% during that window. It also appears to run its duty cycle on a three hour period.
Click to expand...
What you see in the chart is the supply AC current, specifically RMS values, which can be used directly for calculating power usage. The RJ-60 is basically a black box which does not provide any access to its internals. So measuring the supply AC current is the only thing I could do. The attached chart is just a screenshot, live node-red charts are interactive and show exact timing and values of the current in tooltip popups.

RJ-60 duty cycle interval is 3 hours. If the power parameter is set from the RJ-60 console to 65% it means that in each 3 hours cycle it will generate chlorine for 2 hours (drawing 0.7A) and then rest for 1 hour (drawing only 0.05A). Based on this, we know that over 12 hours when RJ-60 is on, the average power drawn is 113.4W. (Sorry, there was a clerical error in my previous post, should be 113.4W, not 103.4W.) So over the period of 12 hours, RJ-60 will use up 1.3 kWh of energy.

There is one minor issue. RJ-60 switches the direction of the electrolysis current. It does so during chlorine generation part of the cycle. You can see it as short drops of the current down to the rest value of 0.05A. The point of time when that happens looks pretty much random, and sometimes, like in the chart below, the resulting duty cycle is increased beyond the set value:

Screenshot 2024-07-31 200033.png
In the longer perspective of several days it shouldn't matter - on average the duty cycle will be close to a set value. To prove it, I added new charts for daily and weekly average aggregates calculated from the supply current. I will publish the results after the data is collected.
 
Thanks for the follow up. Re-reading, I see that you did clearly mention that your on/off times were 8a and 8p - but I guess my eyes were drawn to the pretty picture instead :)

I was still confused about the origin of the 4.2W that you were adding in, but now I see what you were doing - you left the .65 and .35 parts of the equation separate and then added them in the next step. I thought you'd done all the math in one step, and then added in the 4.2W for some other reason (I hadn't checked your math until now, instead just figuring the peak usage based on your graph.)

So, your total draw for the day for the RJ-60 113.4W * 12h = 1360.8 Wh, or, on my electrical plan, $0.15 worth of power.
Multiplied by 30.4 days, that's $4.59 per month. Nice! Less than one jug of bleach!
I think in the month of July I used 23 gallons of 10% at $6/gallon, or, $150 after sales tax.

July and Aug are probably my biggest months for consuming bleach, and I've used 83 gallons so far this year. I'm gonna guess that 8-10 of that was just opening the pool (which I may continue to account for). That doesn't align well with my guess that Jul/Aug are heavy months... I wish I could get the raw data out of TFPool more easily. Think I've found some bugs...

Anyway, I can probably safely assume I'll save the cost of at least 100 gallons ($650) per year, maybe as much as 160 ($975). This thing might pay for itself in just two years!
 
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I've been fiddling with pulling the data back out of the PoolMath backup file, and it looks like I've used 85 gallons, not 83, for the year. Usage in May was 24 gal for 22 days (I opened on May 8), June was 22, July was 21, and Aug is 18 so far - considering my FC is STILL too high, that sounds right. That's putting me on track to use about 130 gal per year, but I do think usage tapers off in Oct/Nov. I closed in November last year.
 
I finished the install of the RJ-60 today. I'd plumbed it in a few days ago, but had a couple of small drips to take care of, and I hadn't installed the control unit yet.

This morning I modified my pump controller to include powering the SWG, got the old ORP-controlled bleach dosing pump out, and took care of those drips. I don't have salt in the pool yet, because I don't have my salinity test kit yet (maybe by Monday??), so I'm still dumping chlorine manually.

I did power it on briefly, to see if it complained about anything, but then turned it back off again in a few seconds after not seeing any complaints.

All I'm doing now is waiting for that test kit so I can figure out how much salt to add (I'm figuring an upper bound of 15 40lb bags, but don't want to bother buying any until I know something more concrete.)

Here's a before and after comparo of the 'pool shed':

Before, with ORP sensor, injector, chlorine tank, and the dosing pump/controller:
PXL_20240624_130054693.MP.jpg

After, with the SWG:
PXL_20240824_153214629.MP.jpg
 

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