Getting ready for SWG

[JoyfulNoise]

There is no need for a check valve before the SWG. That was done because the installer was used to installing tablet feeders where acidic water from the feeder could potentially backfkow into the heater and cause damage. SWG’s only produce chlorine when the pump is running and so there is zero chance of “chemicals” back-flowing into the heater....as you so aptly put it, that’s just more numbskullery to deal with.

Do note that most pool heater equipment manufacturers require that check valve for warranty compliance even though it is totally useless. So if you’re worried about maintaining warranty compliance, leave it in.

 

[Dirk]

Thanks Matt! Right, you resurrected those brain cells! There was a tablet feeder where the SWG is now, so now I understand why the check was there (not why the installer replaced the old one with a new one and put it too close to the SWG!! Habit, like you say. Or profit.). MY MasterTemp is more than 3, probably 6 years old, so no warranty issue (I've never even turned the thing on, and don't plan to, unless I win a lottery!).

So the only question is: can I trust a 2" PVC coupler on just 3/4" of PVC pipe? So close! Otherwise I'd have to buy a new SWG fitting...

Just checked. Yep, about what I expected. $30 to replace that one piece of plastic!

https://www.amazon.com/Pentair-Intellichlor-Replacement-Unions-520595/dp/B0032CHRPY

- - - Updated - - -

Hmmm, I could take the check's flapper out first, and see if that does anything for my flow. That's free...

I wonder how much turbulence is going on, with or without the flapper.

 

[Dirk]

About 6:30 PM and I tested chlorine:
FC: 6.0

Lost only FC0.5 today, and the SWG missed an hour of runtime this morning. So I'll leave the settings as they were:

RPM: 1500
GPM: 21
SWG Hours: 8
Output: 60%

I plan to check the FC each day for a while, at this same time of day (after the sun is off the pool).

 

[JoyfulNoise]

I know that some people push the idea of

“run your VSP at the lowest possible speed as much as you can!!”

but that only looks at one side of the coin - power consumption. You also need to consider proper water circulation and avoiding dead-spots in your pool volume. Some of that can be handled with brushing and running a robotic cleaner but a major part of it also has to do with water flow. At 21GPM and with multiple pool returns, the water coming out of your return pipes is probably weaker than a poor quality garden hose. Water dribbling out of a return is not going to produce good circulation when the pool is unused.

I would suggest trying to maintain at least 25GPM and try to add some “high flow” schedules to your pool pump automation. Even just an hour or two at higher speeds (say 50GPM if that’s possible) will help to keep the water well mixed and avoid dead spots.

 

[Dirk]

Thanks, Matt. That of course makes perfect sense. Trying to pinch pennies on RPM doesn't make sense at the cost of good circulation.

This year SWG season and solar-heater season is starting at the same time of year. According to my ScreenLogic history, the solar was active for around 5 hours. And my panels need 40GPH (2200RPM). So I think I have circulation covered for this time of year. I'll remember your notes come off season.

You're right about the flow from the returns. With my old 2-speed pump, I couldn't even tell it was pumping water at low speed...

It's a somewhat silly pursuit, as I have PV solar and don't really pay for electricity any more. But my plan is to use electricity wisely this first year with the PV, to see if I have any credit come PG&E's true-up time. If I do, I'd rather spend that credit on air conditioning next year, then wasting any on the pool. But good pool sanitation is a high priority for me, so I'll spend the electricity there, first.

 

[JoyfulNoise]

Sounds like the solar controller has you covered. On my pool, I run the spa spillover for about an hour to 90 mins each day AND I also run the rock waterfall for an hour total (three different run times during the day). The waterfall pump pulls water from the shallow end through wall drains and returns the water to the waterfall at the deep end. Between those daily sources of high flow rates and my robot running every other day or so, the water stays well mixed.

Solar PV and solar heating the pool is on the long list of “would’ve be nice to have’s” that my home cane with ...

 

[Dirk]

I had grand plans for little mini cycles, similar to what you describe. I was going to have a master medium-speed filter cycle, both with and without solar. Then a cleaner cycle, to clean and circulate. I was thinking about splitting both the filter cycle and cleaning cycle up, throughout the day, to aid circulation. Then I was going to have a polisher: a high-speed skimmer mode, fire up a few times a day to polish the surface of the daily gunk and also swirl the pool for heat and chlorine circulation. This all before I realized... I'm strapped with a miserly four-schedule ET light. So I can't do most of those fantasy cycles...
I let the PB pick the ET before I knew even what little I know now about it! One of my many newbie mistakes.

 

[Dirk]

I'm a big PV evangelist. PG&E is just going to keep raking us, all they can get. CA is in their pocket, PG&E can pretty much do what it wants here in CA. Their next biggie is the "time of use" they're going to be strapping us all with. (I think it even affects PV users.) That was always in the cards, part of the whole smart meters gambit. They'll get a big money grab during peak hours, and they've got us all building their future infrastructure (solar) on our dime. Gotta hand it to 'em, they know how to make money.

PV is my hope and a prayer that I can stave off some of their attack on my retirement income... PV's not going to get cheaper. In fact, its savings potential is constantly dwindling. So I jumped on board...

And with NG prices where I live, solar was the only way I could get my kids in the pool. Otherwise it would have been just me in the pool, talking to them in their lounge chairs, about how nice my TFP water feels...

- - - Updated - - -

Oh, and I estimated... filtering and sanitizing my pool each day is about the cost of a couple of 100w light bulbs running for 8 hours. And if I want it nice and cozy warm, another four light bulbs for about five hours. That's pretty cool in the grand scheme of things...

 

[Dirk]

SWG Journal


About 6:30 PM and I tested chlorine:
FC: 7.0

Gained FC1.0 today, first time ever I didn't lose any FC in a day! So I guess that means my SWG is working. Yay! I'll try a bit less tomorrow:

RPM: 1500
GPM: 21
SWG Hours: 8
Output: 55%

I'll continue to check the FC each day for a while, at this same time of day (after the sun is off the pool).

 

[kimkats]

I guess it IS working! Nice to know!

 

[needsajet]

You could remove the check valve between pump and filter and the one before the SWG and reduce friction loss at 25 GPM by about 0.8 PSI. I don't think that would make a noticeable difference, so I'm with Matt and wouldn't worry about the 50 or 100 RPM. Neither are needed check valves.

It could have been done with the Flowvis as the check valve in position to protect a replacement heater during a warranty period. You can also leave it as is, and remove the check valve before the SWG and leave the Flowvis as is.

Yep, you'll get an adequate joint with 3/4" bury, provided everything is well done, like old glue removed, pipe smooth, clean and dry, both surfaces primed, good glue coverage on both surfaces, pipe rotated as it's pushed into the socket. Rarely the pipe or fitting aren't a great match, and then all bets are off, but you'll feel if they're wrong for each other because they'll wobble when you dry fit.

Or you can cut right through both the black plastic of the check valve and the white plastic pipe. Then you make lengthwise cuts in the black plastic almost deep enough to get to the white plastic (you'll feel the glue on a hacksaw blade). Then you can chip the black plastic off, sand it all down to round, and have the full distance you want.

You can re-use any fitting using the following method. Basically you cut flush with the fitting, paint the PVC inside with glue and light it on fire. You let it burn for a while, then blow it out. The heat softens the PVC. Then, working somewhat quickly, you push a screwdriver down into the softened glue, creating a gap to separate it a bit. Into that gap, you slide one side of needle-nose pliers then roll the softened pipe onto the pliers and yank it out. To be extra sure, you immediately stick a piece of pipe into the still-warm fitting socket so it stays round. If you don't like the fire or fumes, a heat gun works, but takes longer. It's a good idea to try this method on some waste pipe and fittings to learn it.

I'll use those methods to save a gofer trip or an expensive fitting, but if you're buying stuff anyway, it's usually the least work/grief to buy new fittings. If using heat on a valve, take it apart first so you're only heating the body. That's not a bad idea when gluing as well, just in case any glue drips where it shouldn't.

 

[Dirk]

As much as I like the idea of optimizing flow, however, wherever, I think you and Matt nailed it. My SWG is working at 1500RPM (21GPH), and that is on the low side for circulation. So even if I managed to remove the check before the SWG, I really shouldn't be running my pump any lower.

And the FlowVis stays, I like it in the circuit for system management, even if its flapper is worse for flow than a regular check.

I think I'll take the flapper out of the check before the SWG. That seems to be wasted resistance. And if I really wanted to improve flow, I'd bypass that NG heater, which I've never used and probably never will.

But I may practice either or both of your joint removal tricks. Very handy to have in the tool kit!

I think I could have cut that check at the body, and then left the black collar, and found the pipe and/or fitting to reduce that back down to 2", but that wouldn't have been the best for flow 3/4" away from the SWG.

And the smartest way to this, is to pony up the $30 for the new SWG fitting and fix all this in five minutes.

Curse you pool guy!!

Thanks for the info, guys!

 

[rawb]

Well, I didn't get much work done this morning but I couldn't stop reading this thread once I started....very entertaining and informative! I had all but settled on running my IntelliFlo 24/7 at 1,300 RPM since that seems to satisfy my IC-40 flow requirements and my SWG at 24/7 set to 10% output. Now I'm second guessing based on what was said here about poor circulation, which makes sense. So maybe I should go back to a programmed schedule for both and play around with how long it should run based on my chlorine requirements...like Dirk is doing.

 

[jimim]

I do have a SpeedStir (in my sig!), and would be helpless without it. JoyfulNoise helped me with the salt test. I was using an MO I was taught here, but for the wrong test. I kept adding drops to the vial waiting for it to turn to the brown color the test instructions say is "too far," a deeper color than the original change, trying to figure out when the second change happened, so I could subtract a drop. JoyfulNoise explained that the test is over when the first color change happens, basically from milky yellow to anything else (salmon-brick-red-whatever). So I think I'm square on that test.

What I'm struggling with now is something I just noticed the other day. It was on the CH test, when adding the last drops (the ones you count), I was seeing tiny chunks/flakes in the water. When I picked up the vial and swirled it, the extra bits mixed in. Then I realized my SpeedStir "pill" is really only shaking/vibrating at the bottom of the tube, not spinning. When I turn it off and on, it spins for a few moments, then goes back to just shaking. I have a second "pill" and tried that one, but same deal.

Does anybody else's pill shake like that, or are they supposed to just spin, nice and smooth? Is mine defective?

--edit--

Just occurred to me... Is this the symptom for a low battery?

sorry I’m bringing up a old post but I’m going to finally add salt this summer. I didn’t last summer cause the pool didn’t get done till later in season.

Anyway. The salt test. So once it goes from milky to the brown/ brick whatever color u stop. You don’t keep counting till a darker color change and then stop like instructions say?

thanks. I really like this thread.

Jimi

 

[jimim]

I started to hijack another thread, but moved my questions here, instead.

My CSI has recovered to -0.31 today as the pH has bounced back to 7.8.

I've read here numerous times to "maintain the CSI in the slightly negative range" to avoid scaling on the SWG, which I'd like to pursue. But I had it in my head that "slightly" meant "-0.05" or "-0.1" or something like that. For the first time I've just read (in the other's thread) a specific value recommendation, pooldv wrote "I would tend toward -0.3 as an ideal CSI for your pool because of SWG, plaster and location..."

So... is there a number to shoot for, in my case, that is more specific than "slightly?" Or do I just see what works? My IC40 will spit flakes into the pool, so I can tell when it's not happy, but if I don't see flakes in the pool can I assume none are forming at all on the plates?

Playing with Pool Math, I can see that, if all else remains the same, when my pool gets to 80-85°F, that my CSI will be around -0.4 to -0.1, depending on what I do with pH. And between my newish pebble and the SWG, I am anticipating having to adjust pH for some amount of time. So I can just as easily put it at 7.5 as 7.8, which ever satisfies my CSI target.

Thoughts?

I'm still a little confused on if I'll ever be able to leave my pool alone for a week (not counting testing). It kind of negates the advantage of an SWG if I have to add MA every other day.

TODAY:

FC: 4.5 (I'm targeting 5.5)
pH: 7.8 (This is my current target)
TA: 70 (I've left this alone for months)
CH: 325 (Recent rains, soft water auto fill and rain water experiments have brought this down a bit from 350)
CYA: 75 (or 80 as you all like to round up, based on what I've added it really shouldn't be above 70 (1g liquid, 4lbs solid))
Salt: 3200 (8 bags + 300-ish from original fill)
Temp: 59

Dirk,

i like ur posts cause I’m like u. I get hung up on numbers cause I think I’m going to mess up something. I have been a wreck all winter causexthe pool is closed and I’m worried I’m going to open to scale. All season I was like u last year. Making sure my numbers were right on and everyone kept saying that’s why their are ranges. But I totally get u!

 

[Dirk]

Yah, I still struggle with that. But unfortunately, it's part math, part science and part black art! You can get as far as you can with the math and science, but each pool has it's own personality and you have to listen to what it's telling you. So getting wrapped up looking for just one set of perfect numbers is a losing battle. If your pool was indoors in a temperature controlled environment, and covered from the sun, and nobody ever swam in it, you might have a shot. But it's a pool. A living thing. It bends and twists and ya gotta just try and keep up!

The reassuring news... If you can get within TFP ranges, you'll be in the 97th percentile of great pool care, when compared to what others are getting with pool guys and stores.

 

[Dirk]

sorry I’m bringing up a old post but I’m going to finally add salt this summer. I didn’t last summer cause the pool didn’t get done till later in season.

Anyway. The salt test. So once it goes from milky to the brown/ brick whatever color u stop. You don’t keep counting till a darker color change and then stop like instructions say?

thanks. I really like this thread.

Jimi

I'm now stopping when the color first changes dramatically and stays that way (ignoring the flashes of color before that).

What I came to terms with... My SWG's built-in salt test is wonky. Temperature messes with it, too. The drop test has a pretty large margin of error as well (400, I think). And my SWG has a pretty wide range of operation (typical of most SWGs). So salt is one of the levels that just isn't that critical. I was struggling at first with the test because I was measuring my pool, and fill water, around the 100-300ppm range. Once you're testing in the 3000ppm neighborhood, an extra drop or two, one way or the other just isn't going to matter all that much.

The bottom line is, and the goal I ended up achieving, is to put in just enough salt to get the SWG happy, then a bit more so that I'm not scraping the low end of the range for my SWG (where generation performance and/or temperature swings might make a difference). I'm at 3000 now, my SWG wants 2800 minimum, and shuts down at 2600. So I have a little buffer from the low end, and a bunch of room to grow 'till the top end.

I wanted to start at the low end of the range because chlorine (and I think MA too) increase your salt level over time (and that doesn't evaporate), so starting low-ish means a bit of extra time before the ineveitable water replacement.

With salt, I believe, close enough is close enough.

 

[lightmaster]

To improve your flow, why not bypass your MasterTemp altogether? You said you don't have any plans of ever using it. You could also make a bypass around it so that if you ever did decide to use it, just flip a valve or 2.

 

[Dirk]

To improve your flow, why not bypass your MasterTemp altogether? You said you don't have any plans of ever using it. You could also make a bypass around it so that if you ever did decide to use it, just flip a valve or 2.

I've considered both. That's as far as that project got!

Two nice Jandy valves, or one three-way and a check valve... I'd have to do some math to see if the increased flow/reduced pump RPMs would ever pay off...

You can see in the pic above (#120), I don't have much room, and I'd have to rebuild or replace who-knows-what because my x-pool-guy glued everything right next to the next thing in line.

Too bad Pentair didn't make a dummy for their heaters, like they do for their SWGs. Nice u-shaped one that could slip right in there and mate up with the unions. Or better yet, build their heaters with a built-in bypass.

 

[Arizonarob]

Well, I didn't get much work done this morning but I couldn't stop reading this thread once I started....very entertaining and informative!

This thread really does have it all. Action, adventure, thrills, chills, mystery, and even a little romance, (part were Dirk looks lovingly at the color of his pool during the different seasons.) I read the whole thing yesterday, and now it’s like a series I have to tune in daily to see who shot JR!!