slow and steady chlorination idea- first tests

[duraleigh]

I had forgotten this old thread and glad somebody rejuvenated it. I think it has possibilities.

As far as being impractical, it seems to me setting a couple of jugs of Clorox in the pool would be pretty painless. They would have to be removed for vacuuming, swimming, etc but that seems easy enough with a rope or something.

I also believe that through diffusion, they will continue to provide chlorine to the pool without the pump.....although the pump would need to be turned on from time to time for even distribution. Along those lines, I don't think you would need to set the jugs at different places in the pool as the pump would quickly circulate and even out the distribution.

What I can't figure out is how OP dteremined when jugs were empty. Do ya'll think you could see the cline just by looking into the jug? I know you can on the Liquidator but it is much easier to peer into the liquidator than a jug of Clorox.

 

[Bama Rambler]

By shining a light through the jug you could probably discern the interface. At least enough to determine that the jug is empty. Of course, now I'll have to try it and see.

 

[Beez]

You could always transfer the bleach into a clear container before submerging. Then the cline would be more obvious.

 

[kal2002]

You could always transfer the bleach into a clear container before submerging. Then the cline would be more obvious.

I did exactly that. Out of curiosity, I had to try out the floating chlorine jugs idea last night. The chlorine that I buy comes in the opague gallon jugs. I poured half of one gallon into another opague gallon jug, poked 2 holes towards the top, added water to both jugs. put the caps back on them and let them float in the pool. After a while, I could see that there is a layer of water sitting on top of the chlorine/water mix. I did not poke any holes at the bottom of those jugs but I wonder if I should have. I did not want the chlorine mixture to leach out too quickly. The pump was off when I did all this. It should be on this afternoon. I will find out this evening how well this idea works when I test the pH.

 

[kal2002]

Not pH, I meant FC.

 

[kal2002]

FC tested at 5 ppm tonight. I increased it to 6 ppm last night. I cannot tell if the liquid chlorine floaters worked since I probably did not do it right. I did not add any chlorine to the pool tonight. I poked another hole towards the bottom of each jug (I think I was supposed to do that). When I test FC tomorrow night, it should tell me if these floaters work, I hope.

 

[rikiamanda]

I wonder if this could be the answer for the area under the steps going into my agp where there is very little circulation? A small hole in the top of a bleach bottle set down inside square plastic container? The low circulation and protected area would mean I don't have to worry (much) about it getting knocked over, and the area could just be cleaned when its time to trade out for a new bottle. I think my biggest concern would be the chlorine spending to much time on the vinyl liner and bleaching it.. hmm might be worth trying. I will anxiously await the results of someone much more experienced before I put this one to test in my 15000 gallon science experiment.

 

[Bama Rambler]

I like the idea of a jug under the steps. While my steps have an open bottom and really good circulation, it's still an area that concerns me because of all the stories you hear.

 

[Beez]

Day one into my experiment. I checked the FC level in the spa before turning pump on this morning. Then checked pool after pump had been running for about an hour. FC levels were essentially the same so it appears the spa is not getting "super-chlorinated" by the submerged bleach bottle.

However, this result leads me to a nagging question. I understand how the cline works inside the Liquidator, because it has water actively flowing across it. But in our experiment, the bleach is much more separated from any flow from the pool water. While I understand the diffusion of bleach at the very top of the jug, what induces the bleach to continue diffusing out of the jug once it reaches a certain point? It seems to me like it might just stay in the jug. Anyone?

EDIT: After reading my post, I'm not so sure about the FC level in the spa vs pool. After the pump had been running for that long, the spa FC might have had time to integrate with the pool. I suppose to get a more realistic idea I would have to test the pool side after a very short time of the pump running.

 

[chem geek]

Diffusion occurs when there is a gradient of concentration. The same principle that has concentrated bleach slowly diffuse from the more concentrated region to the area above it also applies to the water in the jug compared to that outside the jug. The water above the bleach in the jug is not at low FC -- it's just not as high as the concentrated bleach below. Circulation of the water above the jug keeps the concentration at the holes lower than what is inside the jug so chlorine diffuses out. As far as how quickly, that's best determined by experiment -- fortunately, one can use a different number and size of holes to change that rate.

 

[Beez]

Diffusion occurs when there is a gradient of concentration. The same principle that has concentrated bleach slowly diffuse from the more concentrated region to the area above it also applies to the water in the jug compared to that outside the jug. The water above the bleach in the jug is not at low FC -- it's just not as high as the concentrated bleach below. Circulation of the water above the jug keeps the concentration at the holes lower than what is inside the jug so chlorine diffuses out. As far as how quickly, that's best determined by experiment -- fortunately, one can use a different number and size of holes to change that rate.

Thanks for the remedial science lesson, Richard! I know just enough to be dangerous...

 

[Beez]

So, in theory, there is no reason that this method won't work the way I am approaching it. If I decide to stick with it I will have to find a more attractive clear vessel for the bleach though. Right now I think my experiment would qualify for a spot on the "There I Fixed It!" blog...

 

[kal2002]

...my biggest concern would be the chlorine spending to much time on the vinyl liner and bleaching it..

This is my concern also although I am doing it the floating way. What if the floaters get trapped/stuck next to the plaster, will it be bleached out even though the mixture inside the floaters is not pure chlorine any longer? I added water to the floaters when I started the experiment because of this fear.

 

[chem geek]

What if the floaters get trapped/stuck next to the plaster, will it be bleached out even though the mixture inside the floaters is not pure chlorine any longer?

The same concern applies to Trichlor pucks in a floating feeder and these are MUCH worse due to the very low acidity in addition to high concentration of chlorine. I've had mounts to stainless steel bars rust when the floating feeder parked itself nearby. I didn't notice plaster degradation, but that is also certainly possible and some have reported that near skimmers if they put Trichlor pucks in them (a no-no) with the pump not always running.

Because the pH is high from the chlorinating liquid or bleach, not low, the greater risk is for some scaling.

 

[anonapersona]

So, in theory, there is no reason that this method won't work the way I am approaching it. If I decide to stick with it I will have to find a more attractive clear vessel for the bleach though. Right now I think my experiment would qualify for a spot on the "There I Fixed It!" blog...

2 liter soda bottle?

 

[Beez]

What I can't figure out is how OP dteremined when jugs were empty. Do ya'll think you could see the cline just by looking into the jug? I know you can on the Liquidator but it is much easier to peer into the liquidator than a jug of Clorox.

I'm thinking the jugs may float when empty. The one that I put in the other day is getting very "light" or buoyant underwater...

 

[kal2002]

Update to the 2 floating chlorine jugs experiment:
8-25-10 - started experiment when FC was at 6.0
8-26-10 - tested FC - it was at 5.0 - poked holes towards bottom of jugs
8-27-10 - tested FC - it was at 6.5
8-28-10 - tested FC - it was at 6.0
8-29-10 - tested FC - it was at 4.5 - added 0.5 gal. of 10% chlorine and water to each floater
8-29-10 - tested FC 1.5 hr. later - it was at 6.0
8-30-10 - tested FC - it was at 6.5

There is still some chlorine left in one of the jugs so I may not have to add any chlorine tomorrow. If that is the case, that means 1 gal of 10% will last 2 to 3 days and that is about right for my pool. The only difference is that I don't have to manually add chlorine every night.

 

[kal2002]

Tested this evening:
8-31-10 - tested FC - it was at 4.5

I had to add chlorine tonight. I dumped the solution from the 2 floaters into the pool. Added .5 gal of 10 % chlorine & water to each floater. Tested FC at 5.5 half an hour later. The weather is getting into the low 100's in the next few days. The chlorine may not last past 2 days in hot weather. But when the weather begins to cool, I may not have to add chlorine to the floaters as often-maybe once a week? I am liking this idea.....it beats not having to add cholorine everyday.

 

[Beez]

Well, one week into the experiment and I'm ready to give up...at least for now.

The bleach migrates out of the jug v e r y slowly. Just to give you an idea how slowly: I sunk one jug last Thursday. Then on Monday I sunk another because I could still clearly see bleach in the first one. Today I grew impatient because it is rainy and I wanted to make sure I had enough FC, so I pulled up the jugs and emptied them into the pool. Combined they raised the FC by 6. One full jug of bleach raises the FC in my pool by 4! So only 2ppm had gone from the jugs and one of them had been submerged for a week.

I realize that this process could be accelerated by increasing the surface area of the interface between bleach and pool water by poking additional holes in the jugs, but the enticing part of the original idea was to use the jugs as they are with no modification.

It is a fun idea to think about, but IMO it is impractical for real usage. Theoretically, the right container with an adjustable opening might work, but if you were going to that much trouble it would be much better to just buy a Liquidator.

 

[anonapersona]

I've got a question, did the jugs manage to keep the FC level above some point? I am thinking that diffusion relies on a difference between one fluid and the other. So that as the FC near the jug got higher, then less chlorine would leave the jug. So, the jug might be a way to insure that FC never got below some level, 2 or 3 or something, although it may be harder to make the FC get to a higher level like 8 unless flow was really high near the chlorine source.

Yeah, a liquidator would be better.