Does salt in a former SWG pool effect pool chemistry using the TFPC method?

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mgianzero

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LifeTime Supporter
Apr 13, 2009
66
Southern California
Pool Size
25000
I switched over to SWG in my pool 13 years ago. But I remodeled it 7 years ago and it's taken a bit of toll on my nice travertine coping. I'm on my third salt cell (still going strong), but my SWG board went out. So, better late than never, I've decided this is a good time to trial a simple chorine pool using TFPC method.

So here's my latest chemistry:

FC 3.4
pH 7.8
TA 70
CYA 55
Ca 660 (I know it's high, my tap water reads 240. I don't know. Should I change it?)
NaCl 3600 (This was because I was using a SWG until it crapped out a few months back.)

So here's my plan:
I'm adding a little liquid chlorine to bump it up to around 5-6 (I like a higher number so I only need to adjust once a week. Sorry guys, but water testing once a week is what I consider reasonable as a pool owner. If it needs more attention than that, I'll never get anything else done around the house!) I'll also drop my pH to around 7.4-7.5 (more effective range for chlorine to work without getting overly corrosive). I'm thinking TA and CYA look about right. I'm figuring I'll leave the Ca high. Does high Ca cause problems with travertine? I know you can get a bit of scaling, which I can see a little on the blue ceramic water level tile. But how does Ca show on white travertine? I just notice the travertine has some holes and pitting. Could the travertine erosion be causing my high Ca levels?

So here's the REAL question ...
I know I shouldn't be listening to the local pool store guys, but this "self-proclaimed expert" states that I need to lower my salt as it "interferes" with the chemistry of my pool. So why is this? I figured I could keep the salt level where it is for two reasons - 1) I could easily revert back to SWG if I decide and 2) the salt serves as a softener, so keep a nice feel to swimmers. But if I need to lower the salt, the only way would be a pool drain, which gets really expensive, not to mention messy, out here in southern California.
 
Salt at those levels is not a problem at all. What they said makes no sense.

High CH tends to lead to calcium scaling. It is possible to manage various levels to prevent scaling, but it is extra work. High CH would not cause erosion, quite the opposite, if anything it would add calcium to the surface.
 
You'll be just fine leaving your salt in the water. Remember a salt pool is a chlorine pool. It's just put in the water differently. Your CH is manageable. Just keep your pH in check and you should be fine.

The only thing you will have to take into account is your CYA. The higher your CYA is on a manually dosed pool, the more diligent you will need to be on chlorine additions.
 
No reason to worry about the salt.
There is a reason to worry about your chlorination plan. Weekly adjustment of FC is not likely to be sufficient. Once you get a read on your pool you can likely get by every other day, but your chlorine will likely be gone in 3-4 days.
 
JasonLion said:
High CH tends to lead to calcium scaling. It is possible to manage various levels to prevent scaling, but it is extra work. High CH would not cause erosion, quite the opposite, if anything it would add calcium to the surface.
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That's what I was thinking. It's probably good to keep my Ca high (or where it is) since this could help to minimize stone erosion.


jblizzle said:
No reason to worry about the salt.
There is a reason to worry about your chlorination plan. Weekly adjustment of FC is not likely to be sufficient. Once you get a read on your pool you can likely get by every other day, but your chlorine will likely be gone in 3-4 days.
Click to expand...

Wait, I sometimes have long call days, not to mention kids activities, etc. You mean the TPFC method only works if I test and adjust my pool every 3 days? What are you testing every 3 days - FC and pH? Seems like most of those chemistry tests don't vary much from day-to-day. But most pool maintenance companies come once a week. There's got to be a "lower maintenance" way of doing this.

I was contemplating a Stenner chlorine injection pump (not sure which one would be appropriate but a figured a 15 gallon tank would be a good size.) I'm estimating that I use 1-2 gallons of liquid chorine a month at this rate with my 20,000 gallon pool. (Will probably go up a bit in middle of summer.) The other option is to replace my salt cell with a tablet feeder such as the Pentair Rainbow 320. The only concern with this is that CYA will just climb too high. What's the latest consensus on this? Seems like we can't all spend this much time checking and tweaking our pools. I would never get through that honey-do list at that rate!
 
We don't teach the methods that pool service companies try to use for weekly service. This usually involves jacking the CYA up very high and then adding large amounts of chlorine when they show up.

Most members are testing and adjusting FC and pH every 1-2 days which takes less than 5 minutes. You have to add FC every few days, a peristaltic pump would do that for you.
 
If you leave your CH that high you will need to keep your pH between 7.0 and 7.5 to prevent scale formation. For the 1st couple of weeks test FC and pH daily and keep a log of the test results and any chemicals you have added. You should see a pattern emerge of how often things need to be adjusted, then you can decide how often to test and dose your pool. The whole process should only take about 5-10 minutes. The CH, CYA, TA and any optional chemicals such as salt or borax can be tested monthly. If you have any kids age 10+ you can always teach them to run the tests and record the results, adds a little math and science to their daily routine.

Some "pool care experts" are overly concerned with total dissolved solids(TDS) and think a high TDS makes a pool more difficult to maintain. Our view at TFP is that TDS does not matter in a properly chlorinated pool. Salt is just one thing that can add to the TDS, high CH is another. As long as you like the saltwater there is no need to drain and replace it. Since your fill water is high in CH draining and refilling is probably not going to lower the TDS much anyway.
 
So am I correct in saying that a tablet feeder could easily get me in trouble with regards to high CYA levels? I know it's probably a cheap and quick way of trying the TFPC method and not having to watch the pool as closely as every 3 days. (Once a week is really all I have time for this time of year. My work can take me away from pool maintenance for a week easily.)

Otherwise, is the Stenner pump method (maybe a little more costly, but not really) a better way to control chlorine and pH without getting into trouble with CYA? Which setup do you recommend?

Don't know if this affects things much, but I have an Intelliflow pump that I run at 35 GPM throughout most of the filtering day. I also have a Dolphin Premier robot (http://www.premierrobotic.com/?gclid=CLvJwbyykr4CFWVp7AodPCUAyA) that I throw in the pool once a week to vacuum at any leaves and scrub the walls and bottom. Works pretty well.
 
mgianzero said:
That's what I was thinking. It's probably good to keep my Ca high (or where it is) since this could help to minimize stone erosion.




Wait, I sometimes have long call days, not to mention kids activities, etc. You mean the TPFC method only works if I test and adjust my pool every 3 days? What are you testing every 3 days - FC and pH? Seems like most of those chemistry tests don't vary much from day-to-day. But most pool maintenance companies come once a week. There's got to be a "lower maintenance" way of doing this.

I was contemplating a Stenner chlorine injection pump (not sure which one would be appropriate but a figured a 15 gallon tank would be a good size.) I'm estimating that I use 1-2 gallons of liquid chorine a month at this rate with my 20,000 gallon pool. (Will probably go up a bit in middle of summer.) The other option is to replace my salt cell with a tablet feeder such as the Pentair Rainbow 320. The only concern with this is that CYA will just climb too high. What's the latest consensus on this? Seems like we can't all spend this much time checking and tweaking our pools. I would never get through that honey-do list at that rate!
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How are you estimating 1-2 gals/ month? In southern California, I would think all that Sun would burn up burn up 2-3 ppm/day. You'll more likely be adding a gal/day. 5 to 10 minutes/day is not too much time out of your obviously busy schedule. The result if you don't spend the time it's going to be a mess that will dwarf your time spent testing.
 

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What? 1 gallon per day? I don't seem to be using near that amount. Is that what people are using for TFPC for our pools? According to our costs for chlorine at $4/gallon that would amount to $1,460 a year just for chlorine! That would completely dwarf the amount of cost to stick with SWG and / or just hire a full time pool guy for his labor and supplies.

With my SWG in the past, I would check and adjust acid levels maybe once a week and be fine. Maybe this TFPC method is not so simple. How much chlorine are most people using for their pools?

How about if I use a tablet feeder on 1/2 dose and supplement with liquid chlorine? Maybe I can by with using less liq chlorine which can be difficult to store at such high volume.
 
Mgianzero, your calculations for the amount of bleach you will need are way off as timerguy guy stated. It takes 96 ounces of 8.5% bleach to raise the FC 3ppm in your 20,000 gallon pool which will be be a more accurate number for the summer months ahead. An average pool will use 2-3 ppm of FC a day during the summer.

How many gallons was your SWG rated for and have you always kept the CYA around 50ish? Your answers might explain why you have gone through so many cells in 7 years. At most, with a properly rated cell and chem levels we recommend, you should have only needed 2 cells.

From just reading the above posts, I suggest for you to find a SWG rated for 60,000 gallons and bring your CYA up to 80, and that will get a lot more time out of the SWG. It seems to me that you do not have the time to do the testing to learn your pools needs and you will just be asking for trouble by not adding enough chlorine this summer.
 
TFPC is about understanding through accurate testing and adding what the pool needs. It is not about just using bleach or some other specific chemical.

As others said, most pools require 2ppm of FC everyday, how you add that is up to you.
 
mgianzero said:
What? 1 gallon per day? I don't seem to be using near that amount. Is that what people are using for TFPC for our pools? According to our costs for chlorine at $4/gallon that would amount to $1,460 a year just for chlorine! That would completely dwarf the amount of cost to stick with SWG and / or just hire a full time pool guy for his labor and supplies.
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It depends on the size of the pool. 2 ppm FC per day in 20,000 gallons is 9.6 gallons of 12.5% chlorinating liquid per month so at $4 per gallon that would be $38.40 per month or $461 if the pool were open year-round (but usually loss from sunlight isn't the same all year). Even at 3 ppm FC per day, that's closer to 1/2 a gallon per day. timerguy's gallon per day would only be for a gallon of 6% bleach assuming 3 ppm FC per day, not 12.5% chlorinating liquid, and it wouldn't be $4 per gallon but more like half that cost per gallon.

Figure roughly $40-60 per month of manual chlorine dosing at 2-3 ppm FC per day in 20,000 gallons (and you may be able to get chlorine at a lower cost in some areas). Exactly how much depends on your CYA level, amount of sunlight, and chlorine demand (how much stuff gets into your pool, especially if you have lots of pollen). Also, the use of a pool cover can cut down the chlorine loss from sunlight.
 
I wish I could find 10% liquid chlorine here in sc no way could I even think about 12%. Last year in the dead of summer I was needing to put in a 96 oz bottle 8.25 I bought at wally world for $3 /bottle daily. I know s/he gets a lot more sunshine in southern California than I do. I did find some 10% at home depot, but it was over 6 mos old and that stock was still sitting there last time I was there a couple weeks ago.
 
ping said:
Mgianzero, your calculations for the amount of bleach you will need are way off as timerguy guy stated. It takes 96 ounces of 8.5% bleach to raise the FC 3ppm in your 20,000 gallon pool which will be be a more accurate number for the summer months ahead. An average pool will use 2-3 ppm of FC a day during the summer.

How many gallons was your SWG rated for and have you always kept the CYA around 50ish? Your answers might explain why you have gone through so many cells in 7 years. At most, with a properly rated cell and chem levels we recommend, you should have only needed 2 cells.

From just reading the above posts, I suggest for you to find a SWG rated for 60,000 gallons and bring your CYA up to 80, and that will get a lot more time out of the SWG. It seems to me that you do not have the time to do the testing to learn your pools needs and you will just be asking for trouble by not adding enough chlorine this summer.
Click to expand...

I think we are misunderstanding each other a little here. I mentioned that I've owned my SWG for about 13 years and changed the salt cell out twice (last was done last year.) So that's an average of 6 years per cell which I believe is expected.

Also, I was keeping my CYA around 70-80 BEFORE I've switched over to non-SWG. Now I'm letting it stay around 50 since I do NOT want to continue using a SWG for my pool - it's ruining my stone and it requires a lot of acid to keep in range. But my SWG was more than adequate for use in my pool. I often times would turn it way down to keep the chlorine level within decent range.

The type of chlorine we purchase out here is the 10%. So if we're talking about 2ppm per day lost, then that calculates out to about 4/10'ths of a gallon per day. That's more than I was using, but still a lot less than 1-2 gallons per day. But, although we never close our pool in winter, we mostly use our pool 6 months of the year and my wife refuses to allow me to put on cover on it. In winter, the pool uses significantly less chlorine due to cold and less sunlight. So, again, I'm thinking "maybe" 1/2 gallon per day is expected ONLY during my hotter months and much less during the colder months.

I guess I need to see what amount of chlorine other people who live in my climate are using as a comparison. But since I'm just starting this whole process of liquid chlorine, it's hard to determine exactly what amounts I'll need so I can determine the size tank for my chlorine injector. I was hoping I could get by with a 15 gallon tank size reservoir - which should get me through a little more than a month in the hotter / more demanding months of the year. Don't these calculations sound more realistic?
 
15 gallons sounds reasonable. You don't want chlorine sitting outside for too long in the summer, as warm temperatures can cause it to break down (lose strength). This happens fairly slowly, so not a serious problem, but a month is about as long as you want to go with 10%.
 
Mgianzero, I'm sorry for not reading the post clearly enough, I took the 7 year remodel as the time when your SWG was installed and that would have made it difficult for anyone to keep putting that much money into a SWG system.

Your new calculations sound very reasonable to me.
 
Guys - Pardon my stubbornness here, but I just don't see how the TFPC method is very practical. According to everyone's calculations, I'd have to go through about 2 boxes (4 gallons) of chlorine a week and test the pool every three days for my 20,000 gallon pool. Purchasing a 15 gallon injection pump would "maybe" get me through a month of chlorine before adding. I'd be stopping by the pool store for 8 boxes (2 gallons per box) every month just to keep stocked. In the middle of summer, with an estimated 3ppm of chlorine use per day --- that's 30 gallons of chlorine per month or 15 boxes I'd be buying every month. Doesn't that seem a little crazy? What am I missing here? This would require a ridiculous amount of work to maintain my pool.

I've owned my SWG for over 13 years and taken care of my pool with weekly (if that) chemical testing. I'd guess I was going through a gallon of acid every two weeks during the summer. The salt would have to be added "maybe" once a year and only a few bags if that. The chlorine was super easy to adjust with the percentage dial (I'd keep FC at around 4ppm). Adding acid was the only real duty and at 2-3 gallons per month, that was not that difficult. If I let things slip (which would happen if we went out of town - can easily be gone a couple of weeks) then I might have to SLAM the pool once a year. But that was mostly it.

I'm trying to be open to new ideas, but I'm thinking I should just reseal my travertine and wash it down when it gets wet and be done with it. I can't see how liquid chlorine (in bleach or pure shock form) would make keeping my pool very easy if it requires this much chlorine and this much attention. I love my pool, but not that much!
 
The Trouble Free philosophy is based on accurate testing and an understanding of the real chemistry that works. It's not specifically about bleach or liquid chlorine.

Since a SWG works for you, then it might be your best choice, especially since you're going to maintain the salt level of an SWG.
 

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