Can Chlorine behave this way ?

[SPP]

Dear Seniors,

This is a follow up from this post :
now-i-am-putting-my-nose-to-work-t10250.html

I need to know if this is a possibility :

I am poor with chemistry, so I want to think in simple form.
Chlorine is supposed to be "spent" or converted to other form when it oxidize contaminants in the pool.
If I get contamination that can not be oxidized at say 3.5PPM FC ( CYA at 20 ) , will the chlorine remain in its initial FC form ?
I am thinking of a battle scenario. If chlorine can't kill the contaminants, it doesn't do its oxidizing work right ? In that process I am assuming it doesn't get "spent"...... is this possible ?

6 divers spent some time in my pool Sunday nite, 18 Jan 2009, completed their training at about 7PM.
I noticed the water lost its sparkle, like becoming very mild cloudy.....ooopppsss...I don't like it. FC 2.5 , CYA 20.
So I thought those are more of visual contaminants from the divers, the kind that my filters will take care of.
I dumped 1 liter of 12.5% chlorine ( should raise by 1PPM ) as a precaution...then it rained so hard till next morning, part of my city got flooded. This is the hardest rain I seen since 2007. I do not know how much water was added to my pool. The overflow pipe sent excess water from the balancing tank direct to the drain.

I set the main pump to run non-stop that night and also the trolley pump gets into action. I was sure by tomorrow night the water will be clear again. 8 hours later FC went up to 3.5. 50 hours later and already 8.3 times total pool water turnover and no chlorine loss at all. I had 2 tablets of Di-Chlor dissolving slowly since 18 jan. I really hate when troubleshooting with tablets in water screwing up my calculation. Any how, 50 hours of pumping and no rain and I am not seing improved result even with 2 pumps running 24 hours non stop, its a cause for alarm. Sand & cartridge filter pressures did not increase at all after the 18th Jan divers out of the pool and even the heavy rain from midnight to 6AM.

My new method which I impleted early Jan, have worked well before the 18th :

"If more than 3 divers use the pool, run the pump non stop till next day, so its 24 hours instead of usual 12-14 hours with no bather load. If on top of divers came heavy rain, run the pump on trolley 9PM to 6AM along with main pump.
If bather load more than 5 divers, I run main pump 24 hours and trolley pump 9PM to 6AM, rain or no rain.

If rain hard only and total duration for the rain is more than 3 hours, I run main pump 24 hours.
I need main pump because the ozone is linked to it."


Between 2nd Jan to 15 Jan, it has been raining very often, but none been as bad as on the 18th.
The pool had been contaminated by 20 divers total, with one day 5 diver in one go and less than 10 swimmers. Average time a diver spend in the pool is 3 hours. Never between these dates the pool loose its sparkle.

So this morning at 06:45AM, I get my pool boy to dump 8 liters of 12.5% bleach, hoping to raise to 10 PPM. CYA is 20.
No rain. FC went up to 10.5 at 18:45. At 02:30PM, the main pump cartridge filter shoot up from 8 psi to 9.5 psi, that is 1.5psi in only 8 hours with no rain and diver. Water turned a bit "whiter" mid day. Slime bag replaced with new washed ones, but nothing extra dirty on it. So I am killing the baddies now. At 10:55 PM FC down to 9.5. So in 4 hours without sunlight, I loose 1 ppm already.

The final question is :
Is it possible that at 3.5 FC when chlorine don't kill tough baddies, chlorine simply stay "put" ?? I thought slowly it will kill baddies and consume itself overtime. :?:

This is how it looks like when it loose the sparkle Jan 8th, 10:20pm.
Photo data as follows.....
Speed 1/20 sec. ISO 200. F Stop 3.5. Focal Length 18mm. No flash. Canon 20D. Cheapo original lens. No tripod.
Pool light color temp : 4,000k HID Metal Hilade. 2 x 150w single lamp in the photo zone. Taken 18jan 10:20PM.

 

[SPP]

After chlorine bombing at 10.5 FC.
Taken 0100AM 22 Jan 09.

Picture data sama as previous.

This is a bit "whiter" than the water of 18th Jan. Its hard to take photo at night.... These two photos are not suppose to show the water this blue.

Many thanks in advance.....

 

[chem geek]

Having a lower active chlorine concentration (roughly proportional to the FC/CYA ratio) means that the chlorine will react more slowly in killing pathogens or oxidizing some chemicals. It's not an either/or thing where at some level of chlorine all of a sudden killing or oxidation starts to happen. It's a continuous process fairly linear with the active chlorine concentration. Twice as much active chlorine, roughly twice as fast.

However, there are some chemicals that don't get readily oxidized by chlorine or that are too big so would take too long. Usually, if these particles are large enough to be visible in the water, then they are often large enough to get filtered out. If they are too small to get filtered out, then if chlorine doesn't oxidize them fast enough, the water will remain cloudy. That's when a clarifier can help consolidate particles so that they get caught in the filter or when use of an enzyme can help speed up oxidation of such chemicals. Shocking with higher levels of chlorine may or may not help depending on the specific chemicals that are involved.

I think when you referred to chlorine tablets, you meant Trichlor, not Dichlor. Dichlor is a relatively fast dissolving powder or granular; Trichlor is what is usually compressed into tablets that are slow to dissolve.

Divers in a pool are likely to be introducing all sorts of chemical compounds into the water due to organics, such as grease, that may be on their equipment. That is a far more significant challenge to water clarity compared to clean swimmers.

Richard

 

[JasonLion]

If there is anything organic in the pool, chlorine will get consumed trying to clean it out, even if there isn't enough chlorine to finish cleaning up everything.

In some situations the chlorine might react fairly slowly. Perhaps the chlorine was getting used up slowly enough for the dichlor (trichlor?) tablets to keep up with the chlorine demand and maintain a steady chlorine level.

 

[SPP]

Thanks very much Richard and Jason....understood.

The pool supply insisted that the 3" tablets are Di-Chlor and they also carry the granular ones for fast dissolved, rated as 90%. It makes no difference to me, I just use them to raise CYA. I have 20PPM now and I shall stop at 25PPM.

At 7AM today, the FC dropped to 8. So its 2PPM lost in 12 hours. It rained today, not too hard but still it is messing up the treatment.

The current typical dive regulator grease is Christo Lube, older regulators used to use clear silicone type. Very water resistant this Christo. Christo lube applied very very little to the regulators, but we will never know to what extend it will mess up the pool water when there are chlorine.

I am just so freaked out that at 2.5 - 3.5 PPM FC, I am not getting the stability from whatever "baddies" or species that produces these mild clouding. Heavy rain dan 5 ( sorry not 6 ) divers in one go seems so fatal. If I were to know that eventually I need to hit high PPM early that 18th Jan night when the water started to loose the sparkle, I could have bombed to 10PPM FC and by today it would be probably remedied if not by tomorrow. I wish there are more pool chemicals I can get like you guys over in the US to speed up the process.

My possible other suspects for now are :

- Mask Anti Fog liquid, only 4 drops per mask though at the max. Baby shampoo seldom used in lieu of anti fog.
- New Wet Suit, direct out of the shop and never been washed.
- All other new plastic gears like fins, some has like wax coating from the manufacturing process.

I am still learning the unique profile of the pool in such heavy rain condition. Only 18 days from completed shocking and I must shock the pool again....I fear the algae will be chlorine resistant soon if not sometime this year.

Anyway, thanks again guys, really appreciate this.

Regards,

 

[chem geek]

If the "90%" they refer to is the Available Chlorine, then that's Trichlor for sure since Dichlor is only 55% Available Chlorine (for dihydrate). Trichlor can also be in granular/powder form though that is less common. I have never heard of Dichlor in tablet form. It should make a difference to you in that with Trichlor, every 10 ppm FC adds 6 ppm to CYA but with Dichlor every 10 ppm FC adds 9 ppm to CYA. [EDIT] Also, Trichlor is more acidic than Dichlor so will cause the pH to drop faster and need more chemicals to compensate for that. [END-EDIT]

I wouldn't worry about algae becoming resistant to chlorine. Chlorine is a broad-spectrum chemical killing method so single mutations don't tend to make algae any heartier. It is true that if the chlorine is low enough to let already heartier strains grow, then those will be the only ones left, but they were heartier to begin with and weren't generally the result of specific mutations in your pool. Chlorine is not like an antibiotic against bacteria where a very narrow and specific mechanism is used for killing whereby a small number of mutations can result in resistance.

I doubt that your cloudiness is algae. If you've got sufficient measurable active chlorine at all times, then you generally don't have algae or certainly not enough to be visible (i.e. chlorine kills it faster than it can reproduce). I'm sure the cloudiness is due to the combination of substances introduced by the diving equipment plus the rains that may add extra organics such as pollen (water droplets often sweep up blown particles in the air -- part of the reason the air seems so fresh and clean after a rain).

Richard

 

[SPP]

Aha, that's comforting on the algae things. Thanks.
I will have to check with the pool supply store, I am now just watching my CYA climb closer.

I think you are right, it is probably some combination of something that I don't know its getting into the water.
Its not improving today even though FC drops to 7 at 18:30PM ( but there is 1 tablet dissolving also ). Still, the chlorine consumption is too gentle compared to my last clouding case which was due to algae. The slime bag is also not getting any significant dirt. My main cartidge filter increased another 1 psi after my pool boy scrub & vacuum the pool...this is a bit unusual though, usually its 0.5 psi increase when scrubbed & vacuumed hard. I am trapping "something" but very slowly.
Let see what happens in the next 2 days. This Sunday divers will jump in again....

Thanks Richard.

Regards

 

[SPP]

FC remains 7ppm this morning 7AM. Probably the tablet is dissolving. It was raining again but not hard.
Water is a bit better but not sparkling.

 

[SPP]

Update

23rd Jan 7:05 PM FC dropped to 6.5

24th Jan 6:35AM FC dropped to 6
24th Jan 7:10PM FC stayed at 6

25th Jan 7:00 AM FC stayed at 6

No more tablet been added since that last tablet on 20th Jan.

Water is better but it is not 100% sparkling yet.
I am sure you guys are right, there is something in the water which is not algae but causing my water to loose sparkle and my filters can't get rid of it quickly like how it would with other contaminants.

This is the longest time I ever run a pump without getting maximum clearity its been full 6 days ( 6 x 24 hours ) today and maximum result not here. The water quality today is usually what I will get after 3-4 days of 24/day hours running on two pumps if clouding issue is more from algae early bloom.

Could it be that this time I bomb only to 10PPM while in December I did exceeded 12+ PPM for a day or two, therefore I am unable to "oxidize" what ever non algae contaminants fast enough ?

EDIT
11 :00 AM, I jumped in the water with my mask. It is true, the sparkle is not there yet. There is a depth marking which I pasted using Scothlite reflective tape. It is red in color. Anytime water is not 100% great, the red color is a bit dull in mid noon. When I dive, red color will be the first one to dissappear ( becomes like brown ) before every other colors will become blue eventually, depending on the depth, water quality and the sunlight penetration of the water.

HHmm confused this time...

Thanks

 

[chem geek]

I just noticed that you've got a slime bag that is supposed to catch particles down to 1 micron and you said that it hasn't been catching anything. For particles smaller than 1 micron to make the water dull, then that is more like a colloid. If you are going to be frequently introducing organic substances into your pool water, such as from divers, and you want your water to be sparkly more often, then you are probably going to need to supplement with something like enzymes to more rapidly break down the small oily substances that are probably getting into the water (probably along with surfactants that are keeping them mixed in the water rather than separating to an oily film at the surface).

I don't know which enzyme products are the best, but know of Natural Chemistry Pool Perfect and United Chemical No Mor Problems though the latter doesn't say it's an enzyme, but I suspect that it is. Obviously, such products are extra cost but your situation is somewhat unique -- most people don't bring divers into their pool. Perhaps others have direct experience with good enzyme products and can give you a better recommendation.

Richard

 

[SPP]

The slime bag works, it always catch greenish particle regardless how clear is the pool. Of course I stop using the slime bag when I think I got a 100% clearity, its to speed up the process only.

When I pull the slime bag out of the water, greenish cloudy water will "leak" from from the bag exterior surface. Slime bag water flow works from inside to outside of the bag. I always get thicker dirt inside the slime bag, dirt that the 10 ( maybe 20 ) micron Pentair cartridge filter will never be able to catch. This is what I don't like about slime bag, one must move it so very slowly out of the water for cleaning. I am also sure its not an absolute 1 micron, its priced too cheap for such specification.

Money for money the slime bag does a decent job. I mean by slime bag not catching anything in this current situation is , it does not trap anything out of the ordinary but only the usual greenish dirt it always catches.

Everytime I wash the slime bag inside part, its dirty. Depending on the pool water quality, the slime bag may get dirt faster than usual if the water not too good.

 

[SPP]

According to Slime Bag, the Jumbo Version can trap sun tan oil that swimmer usually use.

I don't know if this is true but an Asia Pacific representative of Pentair once told me that sun-tan oil damage the cartridge filter. I don't understand his exact definition of damage, he just told me that the cartridge filter element will never work to its fullest capacity again....the only way out is, I have to buy a new one. I did replaced once already and will make it a habit to do so every year.

I am lucky that I have a balancing tank, any oily slime will be obvious on the tiled wall of the balancing tank, since my pool overflows itself entirely unlike pool with skimmer. I mean I do not have any tiles on the pool that is not 100% covered with water, so I will not get slime on pool wall. I hope that those oily slime sticking to the balancing wall means it is not circulating back to my pool.

I will look into the enzymes thing, its just that everything of that sort has to be Fed-Ex from USA, its so complicated for me. BBB was a blessing.

I am still figuring out how to rig a Slime Bag to filter the incoming water into the balancing tank. I can get free filtration that way, I mean no need a pump and so on, its gravity feed. If I can do this, that means before my pump sucks water out of the balancing tank to the zeolite and cartridge filters, it is already pre-filtered by the Slime Bag.

Thanks for your time Richard.

 

[SPP]

One more thing I forgot to tell you, my cartidge filter on trolley ( Pentair ) hardly ever get dirty, its always the Slime Bag.

I am suspecting that the waterflow is too big for it even though it is by the book sized to the pump in a "residential" application.

These are the reasons why I think my Pentair cartridge isn't trapping more dirt :

01. I have the suction direct to the pool and so is the discharge hose. This pump is pumping a lot of water compared to a permanent PVC pipe setting where they are lots of " L" bends and poll inlet branching. Less water friction, flow is too much for the filter. I only read 3-5 psi maximum ( clean ) on the Pentair, depending on where I place the inlet & outlet hoses in relation to the pool water depth.

02. This Pentair does not collect overflowed water that flows to the gutter and later to the balancing tank, like the main pump filter sets. Overflow gutter always has some cement works sort of "chipped-of" and the natural stone of the pool side will also contribute to some dirt build up.

03. The Hayward cartrige filter on the main pump downstream of the zeolite always gets more dirt while it is actually flowing less water per hour compared to the Pentair. I think the slower water flow make the Hayward cartridge filter works better, even though in theory the upstream zelbrite/zeolite filter is 3 micron rated and 70-85% effective.

 

[duraleigh]

Hey, Surya,

This issue is probably a little beyond my knowledge but.........

1. If it's collecting on the OUTSIDE of the slime bag, it's not being filtered out of the water, it's "attaching" to the bag.

2. Anytime I see greenish color (and I do in your picture) my first thought is algae.

3. Anytime a pool is a bit cloudy, as yours has been, I think algae again.

I may be incorrect in my thinking but, oftentimes, the simplest answer is the correct one. Your pool certainly shows signs of algae in the water to me.

 

[chem geek]

SPP says the CYA is 20 ppm and the FC is around 6 ppm and stable. If these measurements are correct, it's hard to imagine much algae present. Also, the water was clear until the 5 divers used the pool and then it got dull looking. I agree that the greenish color outside the bag is very suspicious, but it sounds like he's always seeing that, even when the water quality was clear and the chlorine was stable. He can certainly try shocking again (he's almost at shock level already), but since this is an ongoing problem after high bather load perhaps he can use something additional to clear the water faster.

SPP, as far as a cartridge filter getting damaged by suntan lotion, I doubt that. Yes, you should clean the cartridge filter regularly -- in a relatively clean pool with a pool cover and with an over-sized filter you might be able to clean it once or twice a year, but I know in my own pool where there is plenty of suntan lotion from my wife's nearly daily swimming (in the summer swim season) that the cartridge filter definitely collects it. It's a tan color when I clean the filter which should be rinsed off and then soaked in cleaner (such as real TSP that waterbear suggests here). If your cartridge filter is always clean (and I mean by visual inspection, not by a rise in pressure) in spite of introducing oils and such into the water, then there may be a problem with your cartridge filter.

A maximum 3-5 PSI pressure on a filter (I assume you mean absolute pressure, not a pressure rise by that much) is awfully low and doesn't make any sense for a filter large enough for your pool unless your flow rate is very low -- most cartridge filters can handle higher pressure. The flow rate ratings for Pentair filters as shown here vary with filter size, but start at 90 GPM for a 240 square foot area filter. In my own pool, my 340 square foot cartridge filter has shown up to 28 PSI on the filter gauge with my older pump with the solar on and used to show 15 PSI with the solar off (the filter is rated to handle up to 50 PSI). With my new pump, my flow rates are lower, but I still get 24 PSI with the solar on at 48 GPM. With the solar off and my new pump, the PSI is only 4 with a GPM of 24. With my oversize filter, I have never seen a pressure rise above the "normal" PSI of a clean filter even though the filter is clearly visibly dirty when I clean it.

I'm confused by your setup. You seem to have 3 filters. A sand filter with Zeolite, a Hayward cartridge filter, and a Pentair cartridge filter with the latter being used as a backup with its own pump and on a trolley. Are the sand filter with Zeolite and Hayward cartridge filter in parallel?

Richard

 

[SPP]

Hello Dave,

I am sure the greenish dirt on the Slime Bag outside layer is not algae that comes from my pool water somehow residing on the bag, as in algae from pool water moving directly to the Slime Bag outside layer. Its most likely algae that is pumped out thru the Slime Bag but since the bag is so big, water flow is kind of soft, some algae babbies are so small, it pass thru the filter material and cling bit by bit on to the bag outer layer till it accumulate plenty and thus visible. Those that get thrown back into the pool, I can't see them because its not accumulated enough. I don't get this greenish dirt unless I pump water thru the Slime Bag, I mean I can leave a clean bag the whole day in the water and don't run the pump, it will not become greenish dirt laden. Baby algae pass thru the filter fabric but cling to the outer layer of the bag fabric since the fabric its kind of "hairy". Possible ?

I mean we are talking of a 1 micron rated ( even assuming its only 65% effective ) filter bag that one can see easily its "filtered/outside" side, we are seeing things we don't see in a catridge filter kind of filter since cartridge filter "filtered" side is not so visible. If we break apart a dirty cartridge filter element, maybe we can also spot what dirt that managed to pass thru but still cling on the paper element....possible ?

I am sure I am catching the constant airborne pollutants that may carry algae spores or babies or whatever, so its not an algae locally produced in my pool. My air quality is bad in my place.


Hello Richard,

My main pump is 2HP Hayward, feeding a Hayward Sand filter using zeolite and then it goes to a Hayward Cartridge, so it is series plumbing. From there it branches out to 6 pool inlets. I don't know the spec of a 230v Hayward using 50Hz electric supply but the water flow as measured is only 50GPM maximum. The Hayward is a 120 square feed unit and at 45GPM flow it falls under commercial application. This is why I think the Hayward is catching more dirt than the Pentair.
The cartridge gets cleaned at least 24 times a year.

I know my Pentair is borderline, it is a CC100, a 100 sq feet. The pump its SuperFlo 1,5HP SF1.1. I think I am getting 75GPM or a bit more. So my Pentair cartridge is not so effective I am sure. If only I know TFP much eallier....dang...I would buy the 200 sq feet one.

3-5 psi ( clean ) is very low I know, but if you use smooth wall hoses for suction and discharge like my trolley set up, you will be amazed...do did I....at the low resistance. I even got rid of the original gauge and buy a 15psi max, so that I can read better. The suction hose is never more than 30cm above the pool water line in respect to the impeller, the discharge is only a bit more heigh even though suction hose is +-8 meters and discharge hose +- 10 meters.

Thanks Gentlemen....

 

[SPP]

SECOND SHOCKING

I am not able to bring back the water to its peak glory since the last shocking to 10 PPM.
When water settled to 3 PPM and divers are in again and rain started again, it develops very mild clouding again.

What I am trying now is to shock again and this time to 12PPM.
I just did that this afternoon putting 10 liters 12% bleach which should bring to 12PPM but only got 9PPM instead at 8PM. So I added another 3 liters to make sure by 11PM I will get 12 PPM.

Water already started to cloud more from a 9 PPM level late in the afternoon. I think its killing something.
I am raising to 12PPM because I want chlorine to oxidize what I could not oxidize at 10 PPM. I got no other non chlorine oxidizer option.

Let see what happens in a few days. Will update.

 

[SPP]

That additional 3 liters did not raise to 12PPM, only 11 PPM at 11:00pm.
It has been raining everyday and plenty of water into the pool since 4 days ago.
So I added another 1.5 liters at 11:10 pm and this morning at 6:20AM it register 11.5 PPM only.
I can't say how much the rain or the sun have consumed chlorine in the day time.

The mild additional clouding after the shock is starting to clear.
There is no chlorine tablets in the water.

If my guess is right, I lost about 1ppm last nite to rain alone and whatever baddies there.
Its getting very frustrating with all these rain on daily basis intefering the calculation.

 

[SPP]

Hi guys,

I am trying to calculate backwards on how much the rain have contributed new water to my pool, this way I can tell how much chlorine I lost thru water dilution, if not chliorine loss to some baddies from the rain. In essence rain water is not good for the pool.

My log book stated that on August 26, 2008 the CH was 150-160 PPM
Today its only 130PPM. Assuming 30 PPM lost, if I use the Pool Calculator, it calculated that I have renewed about 19% of my 135,000 liters, assuming no other factor involved. So let say 26,000 liters have been introduced by the rain so far.

If I use my CYA loss, to reverse calculate new water introduced by the rain :
CYA 25 10 August 2008
CYA less than 20 by Dec 27 2008 when I fisrt had my clouding after I had the TF test kit.
I keep adding tablets and CYA went up to 20, I stop there by 21st Jan 2009.
If again I use the Pool Calculator and assuming 5PPM CYA lost , its like me putting in 20% of new water.
Today I tested again and I think I am looking at 15PPM no better, so its 5PPM lost again in just 40+ days. Yes the rain was insane. The Pool Calculator assumed I have put in 25% new water. So total new water is 20% + 25% = 45% ( 61,000 liters )

If I use the CH and CYA loss and make it average, I am looking at ( 26,000 + 61,000 ) / 2 = 43,000 liters
43K liters is 32% of my pool water volume.

Looking at which ever number of new water volume introduced in my pool, it look sad and I am not suprised mild clouding will keep occuring, since those rain water is never very clean, it always flows from around my building too.

THE UPDATE - Raining nearly everyday !!

2nd Jan 2009 6:20AM it register 11.5 PPM only. By 07:30PM it down to 8ppm
3rd Jan 2009 6:15AM still 8PPM. By 7:30PM down to FC 7PPM and first time registering CC at 0.5

4th Jan 2009 My pool boy is absent, so I took reading at 04:00 PM, FC = 6 and CC = 0.2 ( very mild )
In the morning at 3AM to 5AM it rain so hard !!!!

Water is looking good. Its very clear and I think give it another 36 hours of double pumps running, I could get sparkling water if no more hard rain comes.

I think based on 20PPM CYA, Pool Calculator which stated 11 PPM as shock and 14 PPM for Mustard Algae is accurate.
What I can't yet decide is, if it rain hard at night and sunlight is decently strong in day time, maybe I should at least keep 1 night where the FC is 12PPM stable. I have not been able to keep a stable 12 hour level of 12PPM FC because of the rain water interfering the day I initiate the shock.

Will report progress soon.

Thanks

 

[SPP]

This is the water with impovement, 5:30PM its a bit low light and shutter speed is only 1/25 to 1/30.
At this time of day, the sunshade will cast greyish colour to the water....