Serious thought out question about monopersulfate...

[howardpassman]

At least I think I've thought this out. During a discussion yesterday in another thread, I mentioned I use a mineral pack. I've used one for 13 years and this year decided to make a run without it. In conjunction with it, I used monopersulfate. My wife is a bookkeeper through and through, so as you might imagine we track every penny i spend on the pool right down to a $1.00 O-ring. The reason I mention this is because I also use a spread sheet to track every measurement of chemicals, addition of any chemicals, weather conditions, pool use, etc. daily. Hey, I'm retired and I find it fun.

So here's my observation: This year I started without a mineral pack and no monopersulfate. Just good old chlorine bleach. I found I was using an average of 76oz of 8.25% bleach a day at .024 cents an ounce. I buy 3 121oz bottles at COSTCO for $9 and some change. My season last year was 122 days long. At .024 cents an ounce that is $222.52 in chlorine for the season. Not bad, really, except some folks would find it inconvenient to carry 75 bottles of bleach home.

Checking my spread sheet last year, here's how it stacked up: I spent $98 on monopersulfate, generally putting in 2lbs a week at $3.50/lb. Some weeks I only used one pound and quite a few times, based on measurements, I went longer than a week. Keep in mind I check everyday, which wouldn't be possible for everyone. I also spent $90 on a mineral cartridge and an additional $32 on bleach. The total is $220.00. So close to just using bleach that it is scary. Just the convenience of not having to go out and buy bleach every couple of weeks and having everything delivered to the house is nice. But, here's my real finding...

I found when using the mineral pack and MPS, I only need to use 20oz of bleach a day as compared to 76oz without using the combo, keeping the FC at the exact same level.

I am aware that the copper in the mineral packs could cause some staining. I have a black plaster pool and because of that, I may not be able to see any mild staining. The next warning I always hear is that if you ave blonde hair, it may take on a green tint. My daughter is a natural blonde and after swimming in the pool almost her entire life this hasn't occurred.

So for me the combination of mineral pack and monopersulfate hasn't proven to be any more expensive or damaging to the pool or swimmers. It has proven to be a little more convenient. Is there any other reason for me to abandon the combination?

Thanks for considering this.

Howard

 

[pooldv]

I don't know enough about it to comment. But here are a couple of pool school articles on the subject.

Alternative sanitizers and pools--The Truth!!

From this page, Pool School - Definitions and Abbreviations
MPS
KMPS
Potassium Monopersulfate
Potassium Peroxymonosulfate
A non chlorine oxidizer or 'shock'. It is acidic and will cause lower pH and TA. It adds sulfates to the water. Will not break down CC but helps prevent it from forming when used on a regular basis. It will interfere with TC and CC tests unless special reagents are used in testing since it WILL test as CC! A good choice to use in indoor pools that are not exposed to sunlight but really has no advantage in an outdoor pool. It is only an oxidizer and NOT a sanitizer and should not be used as such.

 

[howardpassman]

Thanks pooldv,

I do use a deox reagent when testing my chlorline levels. I used to measure the level of the MPS as chlorine and found that after 2 days, the deox wasn't necessary any longer. Generally, I don't have an issue with CC either way. For me I would welcome the drop in pH. That was what my previous thread was about. My pH was rising daily by a large amount. Chemgeek had the same issue and pin pointed the cause of calcium nodules for me.

I didn't remember the sulfates issue. Does anyone have any input on whether or not that cause any real concern?

Thanks,

howard

I don't know enough about it to comment. But here are a couple of pool school articles on the subject.

Alternative sanitizers and pools--The Truth!!

From this page, Pool School - Definitions and Abbreviations
MPS
KMPS
Potassium Monopersulfate
Potassium Peroxymonosulfate
A non chlorine oxidizer or 'shock'. It is acidic and will cause lower pH and TA. It adds sulfates to the water. Will not break down CC but helps prevent it from forming when used on a regular basis. It will interfere with TC and CC tests unless special reagents are used in testing since it WILL test as CC! A good choice to use in indoor pools that are not exposed to sunlight but really has no advantage in an outdoor pool. It is only an oxidizer and NOT a sanitizer and should not be used as such.

 

[ping]

TFP is all about knowing what you are putting in the pool and what the effects are.

You can continue following what you have been doing and will most likely get away with it just like you have for the last 13 years. You probably have high enough water replacement during the winter to help keep the pool from building up too much copper to cause the problems associated with it.

 

[chem geek]

MPS with silver ions is only approved by the EPA (as a disinfectant) for spas (Nature² got that approval) and not for pools. The reason is that the hotter water temperature is necessary for the MPS along with silver ions to break down into sulfate radicals and to create divalent silver ions that provide faster disinfection. This does not happen in pools. Basically, you aren't disinfecting your pool at anywhere near the speed of chlorine kill times. See this post for comparative kill times of chlorine vs. silver and copper and note that if you use metal ions you should use a combination of copper and silver and not copper alone since (at concentrations used in pools) it does not kill fecal bacteria.

There are many ways of having low cost if you are willing to give up on fast disinfection. There are many "chlorine-free" systems that basically just use algaecides of various types, including metal ions. MPS does not fill in the missing disinfection of fast kill times including dealing with viruses. The risks in low bather-load residential pools are low and the main reason we don't promote the metal ions is that they do have side effects that many have seen. You haven't and that's great, but we deal with tens of thousands of users signed up on this forum and nearly half a million per month during swim season and it would be irresponsible of us to suggest using metal ions knowing a significant percentage of users would have problems with plaster staining or blond hair turning greenish. It's your pool and if it's worked for you and you want to keep doing it no one will stop you.

If you wanted to lower your chlorine costs, you could supplement with algae prevention. If you do that, then you can lower the FC/CYA ratio and that will lower your FC loss. You should be able to cut your chlorine usage roughly in half by doing that (your chlorine usage is 2.85 ppm FC per day based on your numbers). The question is how to prevent algae -- do you use metal ions (copper especially) as you are doing or do you use a weekly algaecide such as Polyquat 60 or do you use a phosphate remover. And of course these other pieces cost as well and as you've found out when you add it all up you don't really save that much. You also could likely lower your chlorine usage just using chlorine alone if you had a higher CYA level. You are nearly at 3 ppm FC per day. Another technique is to use a pool cover that is opaque to UV in sunlight. That would likely cut down your chlorine usage to 1 ppm FC per day or less.

 

[howardpassman]

Thanks Chemgeek and Ping. Being in Maryland I do have to drain 1/3 of my water every fall. Actually, it's closer to 5,000 gallons than 6,000, but it's close. About the only time I don't use a solar cover is in August. As fate would have it, it's only 63 degrees today in my neck of the woods.

Last year I had a CYA of 50 for most of the season. The way I understand it, the higher the CYA, above certain levels (some articles say 20, some say higher) the less FC you have immediately available. So this year I dropped it to 30 for a while and now have bumped it up to 45 to try and get the chlorine use down a little. Is that sound thinking??

I really appreciate the info on the algaecides. I hadn't considered that when coming up with a number for my FC. I do use an initial does of Polyquat 60 at the beginning of the season. Maybe I'll add a second dose later in the year, if that makes sense.

One last question regarding chemgeeks info on temperatures and the use of mineral packs...if I keep my pool at 85 degrees (my wifes preference). Does that make any difference in how well the mineral work?

Thanks for the helpful info. I realize this site caters to many different pool types and locations. Of course I'm just looking for information pertaining to myself and my use. Obviously, I'm not going to be sharing my knowledge, or lack of it, with anyone else, so your input, as always, is greatly appreciated.

Have a great weekend and thank you many times over.

Howard

I'm actually not trying to save money, just the small inconvenience of carry so much bleach home.

 

[cowboycasey]

I'm actually not trying to save money, just the small inconvenience of carry so much bleach home.

Howard, I have nothing to add about metals, but have you thought about a salt water generator? ( I am starting to sound like a salesman but I am not ) It would save you from hauling bleach and from your figures if it lasted more than five years it would be right around the same amount... 220x5= 1100 and a sj60 is $929 or a RJ60 is $1200 might be just what your looking for CircuPool® Systems

the replacement will be where you can save a lot SJ for $549 and RJ for $599
the warranty is 7 years on both these models..
10 years
2200 bleach or metals
1649 SJ
1800 RJ

 

[howardpassman]

Thanks cowboycasey. I've been doing a little reading on this site about SWG. Sounds interesting and I'll keep it in the back of my head.

Thanks again,

Howard

Howard, I have nothing to add about metals, but have you thought about a salt water generator? ( I am starting to sound like a salesman but I am not ) It would save you from hauling bleach and from your figures if it lasted more than five years it would be right around the same amount... 220x5= 1100 and a sj60 is $929 or a RJ60 is $1200 might be just what your looking for CircuPool® Systems

the replacement will be where you can save a lot SJ for $549 and RJ for $599
the warranty is 7 years on both these models..
10 years
2200 bleach or metals
1649 SJ
1800 RJ

 

[chem geek]

85ºF is not enough for the kill times at the level the EPA requires. The spa testing is closer to 104ºF. Nevertheless, you are better than the rather slow kill times at 77ºF. It's all a matter of degree, but while chlorine was studied extensively with kill times against a wide variety of pathogens, the same cannot be said for the silver/MPS combination. We know that MPS doesn't oxidize ammonia (at least not very quickly) and probably not monochloramine either so you'll need chlorine to get rid of that bather waste. Our philosophy is that since you need chlorine anyway since it handles bather waste the best of most any chemical AND it also prevents algae growth if the FC/CYA level is sufficiently high enough, then why not just use ONLY chlorine.

Of course, that's just one way of managing a pool. You can, as I wrote, use a lower FC/CYA level if you supplement with some way to prevent algae growth since algae is harder to kill than most pathogens such as fecal or other bacteria, viruses, and some protozoa and oocysts (except for Crypto).

With a pool cover, IF it is opaque to sunlight, then your CYA level isn't that important, but what IS important in terms of the rate of chlorine use in the pool is the FC/CYA ratio. If your pool did not have the cover or if the cover was clear so that your pool was exposed to sunlight, then a higher CYA level even with proportionally higher FC level actually uses LESS chlorine because of a CYA shielding effect. If your cover is opaque, then just focus on the FC/CYA ratio. The CYA level probably won't change your chlorine usage rate at the same FC/CYA ratio.

 

[howardpassman]

Thanks again for sharing your knowledge. Sometimes I seem obstinate, but I'm really just curious and dogged at getting an answer I can understand within my limits.

 

[Swampwoman]

Howard, I have a dear friend who for 20 years has used copper sulphate and liquid chlorine to manage his pool, which most times is a clear as my own. He actively keeps his ph lower to avoid staining. He started all that because he figured out the pool store was useless and instead took the advice of an elder colleague (they're chemical engineers.)

After 20 years, last year, his wife's hair turned green. Now she wears a bathing cap and is generally afraid to trust the water. I feel bad for them, but that's for them to work out.

From what I've observed, he generally has FAR fewer problems than friends who use pucks, but might have more difficulty getting enough control to handle large parties than say, ME with TFP .

I gave him a Taylor k2006 for his birthday (hard to find/ more expensive in Canada) which he was very geeked about (for the FC, PH and CYA control/precision). We tested his water and it actually turned out he was pretty much running TFP parameters, with slightly lower CYA and FC than I'd personally be comfortable with but not too far out of range.

The way I figure it, whether he decides to wean from copper or not is entirely up to him -- at least now he can more tightly control his parameters and make informed choices about treatment strategies.

I think with any kind of maintenance, its all a matter of tradeoffs. Eg. Willingness for partial water changes (CYA or too mich copper). Willingness to maintain and replace a salt cell and possibly use a lot of MA to control ph, especially if on well water...but no lugging of chlorine Willingness to lug chlorine to avoid handling more MA or change well water in a vinyl pool with water table issues (that's my own personal tradeoff).

At the end of the day what matters isn't as much the actual action as being informed/controlling the variables to get the intended result. The real problem with copper is managing the balance/concentration and at the same time implementing effective kill times. For me, chlorine is just easier - a single, known variable that I can control in tandem with CYA.

 

[howardpassman]

Thanks swampwoman. I always appreciate input. Not that I consider your friends incident a mystery to be solved, but I immediately wonder what size mineral pack they used relative to pool size and if they used any additional sources of copper. Maybe an algaecide or something. I've used two makes of mineral systems. Zodiak Nature 2 and Frog. Both were sized very close to the size pool I have in number of gallons.

Back in the day when we might have a heavy bather load I used an erosion feeder and my FC was higher. As a matter of fact, I quit using it because if the pool didn't get much use and stayed covered the level of chlorine would go way up. Since I'm retired an can check it and add bleach every morning, along with pouring a few cups of coffee down my own throat, I don't have an issue. Looking back on my spreadsheet I find that last year, by using the mineral pack, MSPS and hand adding bleach everyday, I could keep my FC within 1ppm of my target. I kind of like that.

I'm definitely not trying to influence anyone else. I was just curious about my own situation.

Have a great day!

Howard, I have a dear friend who for 20 years has used copper sulphate and liquid chlorine to manage his pool, which most times is a clear as my own. He actively keeps his ph lower to avoid staining. He started all that because he figured out the pool store was useless and instead took the advice of an elder colleague (they're chemical engineers.)

After 20 years, last year, his wife's hair turned green. Now she wears a bathing cap and is generally afraid to trust the water. I feel bad for them, but that's for them to work out.

From what I've observed, he generally has FAR fewer problems than friends who use pucks, but might have more difficulty getting enough control to handle large parties than say, ME with TFP .

I gave him a Taylor k2006 for his birthday (hard to find/ more expensive in Canada) which he was very geeked about (for the FC, PH and CYA control/precision). We tested his water and it actually turned out he was pretty much running TFP parameters, with slightly lower CYA and FC than I'd personally be comfortable with but not too far out of range.

The way I figure it, whether he decides to wean from copper or not is entirely up to him -- at least now he can more tightly control his parameters and make informed choices about treatment strategies.

I think with any kind of maintenance, its all a matter of tradeoffs. Eg. Willingness for partial water changes (CYA or too mich copper). Willingness to maintain and replace a salt cell and possibly use a lot of MA to control ph, especially if on well water...but no lugging of chlorine Willingness to lug chlorine to avoid handling more MA or change well water in a vinyl pool with water table issues (that's my own personal tradeoff).

At the end of the day what matters isn't as much the actual action as being informed/controlling the variables to get the intended result. The real problem with copper is managing the balance/concentration and at the same time implementing effective kill times. For me, chlorine is just easier - a single, known variable that I can control in tandem with CYA.