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Why Only 1PPM Coming Out?

Posted by ncrealestateguy (My Page) on
Thu, Sep 16, 10 at 7:22

I have an IC 40 SWG. Most of this summer I could not get enough chlorine in my pool. Usually less than 1ppm. Even if I "shocked" trhe pool for 24 hours with the SWG, it did not increase the chlorine level past 1ppm. It is absolutely clean of deposits. It is running at 80% for 14 hours per day.
So, I did a test yesterday of the water coming directly out of the cell, and it read 1ppm.

1. What should the reading be coming straight out of the cell?


Follow-Up Postings:

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RE: Why Only 1PPM Coming Out?

Need the rest of the readings, especially CYA level. What pump?

Scott


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RE: Why Only 1PPM Coming Out?

I will get them all later today...


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RE: Why Only 1PPM Coming Out?

The flow rate of the pump has an impact to the exit chlorine rise. The IC40 produces 1.4 lbs/24 hr so in order to have a 1 ppm rise from input to output, the pump flow rate would need to be about 116 GPM. But this also assumes that the chlorinator is working properly and unless you are usiing a FAS-DPD kit, the error in chlorine measurement can throw of this calculation. So if the chlorine rise is only 0.75 ppm, then the flow rate would be only 87 GPM. So the 1 ppm rise could be reasonable.

Also, you shouldn't need more than 1 ppm rise in most cases anyway. If you have at least one turnover per day then a full 1 ppm rise will occur per day in the pool. 2 turnovers = 2 ppm. If the CYA level is set correctly (60-80 ppm), then the UV extinction should be no worse than about 25% and the chlorine residual should be about 4 ppm which is ideal for a CYA of 80 ppm.

Just for comparison, my SWG prooduces 1.45 lbs/24 hours and I have it running at 20% for 6 hours per day producing about 0.4 ppm in a 20k pool for a residual of 3.5 ppm.


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RE: Why Only 1PPM Coming Out?

Thanks mas985.

My numbers are:

salt level = 3200
cya = 10
calcium = 250
phospahtes = 1000
ph = 7.0
TA = 100

Sounds to me, then, that my phospahate and CYA levels are not allowing my chlorine levels to stack up.
So, I am assuming that if I raise my CYA level, and get the phosphates removed, the 1 ppm output of the IC40 is enough to keep me at about 3ppm?

Thanks.


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RE: Why Only 1PPM Coming Out?

Phosphates shouldn't matter much. Even though they encourage some algae growth, if the CL level is correct, then algae can't grow anyway. The CYA level is the most important and you should target at least 60 ppm. With only 10 ppm, you are probably losing everything put into the pool each day. So if you raise CYA, then 1 ppm will be more than enough and you will probably need to turn it down.


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RE: Why Only 1PPM Coming Out?

quote" Phosphates shouldn't matter much. Even though they encourage some algae growth, if the CL level is correct, then algae can't grow anyway. "quote

I completely disagree with this statement, this summer I saw several pools with a solid 3 and a 60 which had mustard algae.
Trust me on this people, get rid of your phosphates and clean the filter a day or two later. Phosphates are always algae food.
And don't believe for a minute that running a 1 FC with 60 to 80 CYA will work in the summertime, you need a 3 to 4.

I do agree on the stabilizer. The chlorine being generated is most likely being consumed by it's oxidation of items and direct sunlight.

See ya,
Kelly


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RE: Why Only 1PPM Coming Out?

Thanks guys.
I added CYA, and phosphate remover. Man, that phospahate remover is expensive, ($53/32ozs) but it only takes 12ozs for my 30,000 gallon pool.
I will wait for 48 hours, backwash, retest for phosphates, and see if the chlorine level starts going up.


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RE: Why Only 1PPM Coming Out?

There have been many debates on this issue on both TFP and poolforum. The concensus is that the only reason that phosphates cause problems in pools is because the chlorine level is too low for the given CYA level. If the chlorine level is correct, then phosphates will not cause any issue at all. Several people on both forums sucessfully operate their pools with very high phosphates (> 3000 ppm). The key to have the appropriate CL level for a given CYA level.

Also, I did not mean the residual was 1 ppm only the added chlorine per day (i.e extinction) was 1 ppm. For a SWG pool, you should have a residual that is at least 5% of the CYA level or 3 ppm for a CYA of 60 and 4 ppm for a CYA of 80.


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RE: Why Only 1PPM Coming Out?

I have a IC-40 in a 16K gallon pool. Never even tried running it with a CYA at 10. But at a CYA of 40 I ran the unit at 60% duty cycle, 10 hours/day. I raised the CYA to 70ppm and lowered the unit to 20% duty cycle.


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RE: Why Only 1PPM Coming Out?

My general rule:

Tablet or daily dosing with bleach : CYA @ around 40ppm and free chlorine at 8% of CYA's level.

Salt Cell: CYA @ 70ppm and FC @ 5% of CYA.

If Total chlorine is more than .5 ppm higher, bring the pool to shock level.

Organic phosphates can exacerbate a problem but won't be a cause. Keeping on top of your pool's chem levels with a high quality kit is one of the best ways to ensure this.

Scott


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RE: Why Only 1PPM Coming Out?

I am usually pretty good at keeping my chemistry right on. The day I realized that I needed to add salt is when I also should have checked the CYA level.
I am glad to know that my $500 salt cell is working correctly.


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RE: Why Only 1PPM Coming Out?

I had this same issue this summer and it turned out to be an algea issue that I couldn't see. The IC40 was keeping it just in check but consuming all the chlorine. I had to run my IC at 100% for 12 hours a day and CL wouldn't get above 1.

I spent some time at TFP and learned a lot so after a proper shocking with bleach until my CL loss was less than 1ppm overnight and getting my CYA level set right, I was able to get my IC-40 down to 18% for 7 hours and my CL stays at 5-6 now.


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RE: Why Only 1PPM Coming Out?

ncrealestateguy, any follow up?

Scott


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RE: Why Only 1PPM Coming Out?

UPDATE:
After putting in phosphate remover, my level went from 1000ppm down to less than 500. I may do one more dose to get it closer to zero, even though the pool girl said 500 was tolerable.
My chlorine level is now 2.6...yeah!
But hear this... I put in 5 lbs of CYA, 4 days ago. The initial level was 10ppm. I checked it myself at home and took a sample into the store... both readings were still at 10!
How could this be?
My pool is 30,000 gallons.


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RE: Why Only 1PPM Coming Out?

What did you use to test with?

Scott


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RE: Why Only 1PPM Coming Out?

Scott,
I used the TF-100. The pool store used whatever it is they use.
Should I just add 5 more pounds?


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RE: Why Only 1PPM Coming Out?

It can take up to a week for the CYA to dissolve so I would be patient. Also, I wouldn't waste your money on phosphate removers. Have a read of the link below. Here is the important part on Phosphates:

"Phosphate Levels and Algae Control by Chlorine
There is a myth of not being able to control algae by chlorine alone and that high phosphate levels must be lowered. Though phosphate levels do influence the rate of algae growth, phosphate removers only lower orthophosphate, not organic phosphates, so may not always completely stop algae growth and nitrates are also a limiting growth factor. Phosphate removers should be seen in the same vein as algicides that inhibit algae, but may not prevent it completely. Chlorine alone can be used to control algae if the FC/CYA ratio is above minimum levels (see chlorine/CYA chart described above)."

The most important part is in the last sentence, the chlorine to CYA ratio must be kept at the correct level and if you are trying to kill algae, that requires a 40% chlorine to CYA ratio until the algae is dead. Until the algae is completely dead, the chlorine consumption will be quite high. After the algae is dead, you can then lower the CL level to 5% of CYA.

Here is a link that might be useful: CPO Training


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RE: Why Only 1PPM Coming Out?

MAS,
I would think that the CYA is dissolved if I do not see it laying on the bottom of the pool, as I did for the first two hours or so.
Something is going on, because my chlorine levels are now at 2.6, where they were at 0. Either the phosphorous that was removed is now at a level that enabled the chlorine jump, or there actually is a higher CYA level in the pool, and it is just not showing up on the tests.
I suppose I can wait for another day or two, but I really can not imagine that the CYA is not fully dissolved by now.


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RE: Why Only 1PPM Coming Out?

What Mas said is true. Keeping the FC-CYA level where it belongs and algae is dead before it can multiply. If the ratio goes south, the organic phosphate are what I believe are removed by phosphate removers, can exacerbate the problem. Inorganic phosphates are benign.

What brand of CYA did you add? Broadcasting it over the pool is not normally the way it is added.

If the water is under 80 degrees when testing with your kit, wait a full minute before the second stirring. CYA is notorious for it's slow rise. I usually add it to a skimmer after a backwash, when I need to add it.

I suggest you brush the bottom. You will likely see some dust. It's likely the CYA powder. The bottom of a pool not used much will be pretty short on circulation.

Scott


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RE: Why Only 1PPM Coming Out?

Scott, MAS985,
You guys are the experts, so I went out there and brushed down the entire pool.
Answer me this: If the CYA takes so long to dissolve, then why is it better to dump it down the skimmer? Won't it just go through the pump and get hung up in the DE filter?
Also, if the CYA is still at 10ppm, then wht has my chlorine level shot up from 0 to 2.6. Can a reduction in the phosphates alone do that?
BTW, my water temperature is about 78 degrees.
Thanks for your help. I will retest again either tomorrow or Wed. and post back.


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RE: Why Only 1PPM Coming Out?

Because it dissolves pretty slowly and hanging a sock full of it in front of a return is pretty unsightly.

Doing it after a backwash is best because it does cause a temporary rise in pressure for a day or two. It'll take a while to not just get in but to also be more evenly distributed. A low turnover pool will take a while under a normal for that pool set of filter cycles. Commercial pools, with their higher turnover rate get it a bit faster.

Sorry if that seemed a bit convoluted.

Scott


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RE: Why Only 1PPM Coming Out?

Quote: "if the CYA is still at 10ppm, then wht has my chlorine level shot up from 0 to 2.6. Can a reduction in the phosphates alone do that?"

Perhaps, removing some food for any algae. Also I think the CYA test is generally only good for +/- 10ppm accuracy, so you are undoubtedly already over 10, and will climb through the week.

My PB screwed up the sequence on my pool (maintenance tech cleaned out the filter 3 days after they added CYA). I went from around 10 to 40ppm in those three days. After we collectively figured out the screw-up, they came back and added the remainder of CYA to reach 70ppm. At 40ppm (when I thought it was 70) I had 5ppm chlorine at a 60% duty cycle, and once I really had 70ppm, I have the same 5ppm chlorine with a 20% duty cycle (IC-40 SWG, 16K gal pool, Florida summer sun, FAS-DPD testing).


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RE: Why Only 1PPM Coming Out?

CYA tests can be a bit tricky so you need to do them consistently to get good results. First off the TF-Kit only measures down to 20 ppm so I am not sure how you are telling that it is less than that. Adding 5 lbs should have raised CYA by 20 ppm but how do you know it was 10 ppm before if the test kit does not measure that low? Also, pool stores tend not to do CYA testw very accurately so I wouldn't go by that. The FC level seems to be increasing which to me would indicate the CYA is working or at least starting to.

I usually use the sock method when dissolving CYA. This works better for me since I know when all of it is dissolved. The skimmer method should work also but with a DE filter, you can't backwash until all of it has dissolve but you can't tell since it is in the filter. Also, I would definitely not put CYA on the bottom of the pool especially if it is plaster as this can damage the surface, it is an acid albeit mild.


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RE: Why Only 1PPM Coming Out?

The graduated cylinder for my kit is in 10 ppm increments.

Use the pool calculator to figure how much of what you need.

There is also an I-Phone app version. I am hopeful he is writing am Android version too but for now, I use the web version.

Scott

Here is a link that might be useful: The Pool Calculator by Jason-Lion of TFP


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RE: Why Only 1PPM Coming Out?

Mas985,
Even though the beaker is only graduated down to the 20 mark, I kept on adding the reagent until the dot dissapeared. The amount of reagent that it took to do this equated to another 10 gradations.
I am pretty confident with the two tests... they both read the same values 3 times now. That tells me they are both correct.
I have always read that you should not put chemicals, especially acid, directly into the skimmer. Add to that, that CYA are pretty hard flakes, I would think that this method is not too good for the pump. I tossed mine to the bottom of the pool and then brushed the stuff until it disappeared. I hope it did not hurt the PebbleTec finish.
When it gets light out, I will take another sample for chlorine and CYA.
Scott, I use the pool calculator all the time... good stuff.


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RE: Why Only 1PPM Coming Out?

I doubt you hurt the PT finish.

Just don't add too much at once. 5 pounds every other day is usually fine assuming the filter is 36 square feet or greater, until the near normal and recommended amounts are tested for and achieved.

If you have a heater, the sock method we mentioned earlier is a better solution if its being used. Wish I had mentioned that earlier.

Scott


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RE: Why Only 1PPM Coming Out?

To target 80 ppm, you will need a total of 20 lbs of CYA so you still have a ways to go anyway. I would strongly suggest using the sock method if for no other reason to make sure it is actually dissolving.

There is a theory that some bacteria may actual break down CYA but I don't think it has ever been proven. I have had CYA dissapear without water loss so I know it can happen but it is usually pretty rare event.


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RE: Why Only 1PPM Coming Out?

I just got back from the pool store... CYA is now 16. It has been 5 full days now. The pool store says that they have been experiencing this phenomena for about a year now. The inside theory, according to him, is that all CYA is manafactured in China, and that the quality control is poor. So for the past year, they have been seeing hit and miss as far as the CYA actually bringing up levels. He says that they have tried 3 brands, and all are the same. The brand I used was REGAL.
I will give it one more day, and then I will add more of a different brand from a different store.
Have any of you insiders heard of this rumor?


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RE: Why Only 1PPM Coming Out?

Never heard the rumor. Generally, Regal has quality stuff.

As for cost effectiveness, HTH works fine and is available at Wal-Mart. Works fine.

Scott


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RE: Why Only 1PPM Coming Out?

I have heard about bad CYA and I think it was over at TFP but I haven't done a search. It doesn't surprise me though. I use Lowe's CYA (Kem-tec?) as it is pretty cost effective and reasonably priced. So far, I haven't had an issue with it.


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RE: Why Only 1PPM Coming Out?

Well, I just added another 4 pounds of the Chinese stuff... I will test again in two days and post. I really feel like I was robbed. Either by the pool store or by the Chinese.
Scott, thanks much for the tip on the Wal Mart HTH. I imagine it is cheaper too.
Mas985, I, too, read on TFP that certain kinds of bacteria can eat away at CYA. I happened to have a good test for coliform bacteria that I have on hand for my well, and it showed no bacteria. I do not even know if this is the type of bacteria that would eat away at CYA, but it is nice to know that my pool is clear of any of this stuff.


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RE: Why Only 1PPM Coming Out?

The bacteria only grow in am uncirculated, unfed pool such as one that is winterized.

Scott


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RE: Why Only 1PPM Coming Out?

OK...3 days after I added the second dose of 4 more pounds for a total of 8 pounds... I am at 30ppm. PoolCalculator says it should have only taken 5 pounds to go from 10 to 30.
I am starting to think that the stuff is just of poor quality. I will go to Walmarts and get some HTH.
Thanks for all the help.


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RE: Why Only 1PPM Coming Out?

Any chance you are off in your pool's capacity?

Scott


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RE: Why Only 1PPM Coming Out?

No,
All of the other calculations over the last two years, that I do with poolcalculator.com are correct. I will do one more test today... it will be over a week since the last addition. We will see where it all settles out at.


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