Local area pool store water testing descrepancies

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kimkats said:
When you say "shock" what do you mean? If it is powder stuff please do not add any more as it adds stuff you do not need and IF your CYA test is even close to correct you are getting close to the upper end for that level.

:kim:
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Yes, it's powdery/very fine granule type stuff that dissolves relatively instantly when throwing it in the pool. If that's not recommended, then what should I throw in in lieu of? Just store brand/Clorox liquid bleach?
 
Swampwoman said:
Mijmc, welcome. For swg, our recommended levels of operation are 3-5 ppm for 70 ppm cya, 4-6 ppm for 80 cya (see [fc/cya][/fc/cya] - this ratio is important and underpins the TFP method. )

So from your posting, it sounds like you've been operating closer to our "minimum, never drop below this number." For an swg, that means its entirely possible the ccs are coming from the FC's clearing of nascent algae. The TFP way would have you target 5 ppm during production so tat you don't drop below 3 when the swg is off.

"Shocking" weekly likely kept you from an outbreak, but would/should be entirely unneccesary if you operate at TFP recommended levels. By so-doing, I've now gone 5 years without ever needing to "shock".

Now that you're getting your own test kit, you should be able to dial in your swg to avoid ever needing to shock. And if you do need to bump it up a bit, just use liquid chlorine (if you wanna talk sports with the pool guys) or bleach if you want grocery store convenience ;)

You'll want to confirm that youre at 70ish cya once you have your kit. I think you're going to enjoy the informed control you're about to get over your pool. It really simplifies things over time ;)
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I think you're correct in regards to the lower, minimum operating range. And all along, (based on mine & pool store testing) I have believed that my chlorine was relatively on the high side...a bit confusing. :(

As I had indicated, I have not been doing the weekly shock thing this summer (per my & store readings and what I had read here) as I didn't think it was necessary.

If my SWG recommended target number is 5 ppm, and, as you think likely at the minimum 3, do I just turn up my SWG percentage? Currently, it's at 60%. If my salt ppm happens to be on the low side (I'm not sure if it is as my PDA reads 3200 ppm, which, if accurate, is in the recommended range) could that be a contributing factor to low free/total chlorine?

Thanks!
 
Yes, you would increase the SWG %. Most of us don't worry about the salinity levels until our SWG tells us that we are low. The increase in salinity shouldn't impact your production as long as it is producing now.
 
kcindc said:
Yes, you would increase the SWG %. Most of us don't worry about the salinity levels until our SWG tells us that we are low. The increase in salinity shouldn't impact your production as long as it is producing now.
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I'm at 60% now, so increase to 70, 75% or higher?

Do you mean when PDA reading actually says low salt? What if recommended range is 3200 ppm, but say reading is at 2700 or 2800 ppm (PDA or Aqua-Link Control Panel readout is not saying "low salt") doesn't salt have to be added to get the production required for size pool, etc. Are you saying that a low salinity reading doesn't have an effect on chlorine production of the SWG? My understanding has been if the salinity reading is low then there's no way it can produce the needed/recommended amount. How does one know for certain that the SWG is producing, especially if one keeps adding liquid chlorine, bleach, shock, etc.?

Thanks!
 
You'll have to play around with the % to see what works. It is best to bring your FC up using bleach and use the SWG to maintain the level you want.

I wouldn't worry about the salt level until the the SWG display lights says low salt. I don't know your particular cell, but as long as the lights are stating it is generating chlorine I wouldn't worry about it.

You should have to worry about your cell until it gets old or has any scale and needs to be cleaned. Keeping your CSI in the negative range will help keep your SWG scale free and will increase the life expectancy. Not managing your CSI can cause you to clean more frequently and lead to premature cell death. You can calculate your CSI using pool math.
 
kcindc said:
You'll have to play around with the % to see what works. It is best to bring your FC up using bleach and use the SWG to maintain the level you want.

I wouldn't worry about the salt level until the the SWG display lights says low salt. I don't know your particular cell, but as long as the lights are stating it is generating chlorine I wouldn't worry about it.

You should have to worry about your cell until it gets old or has any scale and needs to be cleaned. Keeping your CSI in the negative range will help keep your SWG scale free and will increase the life expectancy. Not managing your CSI can cause you to clean more frequently and lead to premature cell death. You can calculate your CSI using pool math.
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Okay. My SWG is a Jandy Purelink 1400. I get my filter internal grids cleaned out every 6 months as recommended by the manufacturer. The service company also checks my SWG at the same time...to date, cell has always been very clean with no scale build-up, etc. All my EQ is now 2 years old as pool operation commenced in une of '14...so this summer is #3.

Thanks!
 
The SWG will achieve it's full output across a fairly wide range of salt concentration. When there's not enough salt, the system detects the condition and lets you know. TFP recommends keeping salt around 200 to 400 ppm above the recommended level, but that's just to provide a buffer for error or where there is a lot of rain or splashout. One of the respected experts here is challenging this recommendation, so hopefully it will be updated. Keeping salt at a level that satisfies the salt cell controller works fine.

A salt test kit will provide a more accurate salt reading than the SWG controller, if you'd like to know more about your salt level. The Taylor K-1766 is the most commonly recommended test kit.

For your pool at 35,000 gallons, and the Jandy 1400 at 1.25 pounds output per 24 hours, I'd be inclined to set it at 100%. To provide around 2.5 ppm FC replacement per day requires 14 hours run time at 100% in your size of pool. Pools vary greatly in FC demand, but the most common reported swim season numbers range from 2-3 ppm FC per day.
 
Nectarologist said:
Hi Mijmic. The pool stores' results can be due to a number of reasons. The machines themselves are capable of testing properly and better than any manual test kit (not because of the test kit but because of the human error potential is much greater with a manual test kit). The problem with pool stores is that they likely do not run regular controls on the machines. A pool store using a testing analyzer should be running control samples to ensure that the machine is capable of testing properly. Think of getting blood work done at a hospital. The machines they use are very accurate and they spend a lot of time and money to ensure they are working properly (calibrated daily, control samples run several times per day depending on machine). A pool store wouldn't do this. They have machines that have the capability to be accurate but they don't invest the resources to be sure they are operating properly. That being said even the same type machine in a hospital lab will test different than the same make/model right next to it, testing the same sample. There is an acceptable variance. I don't trust pool stores because they likely don't run control samples to double check the results. If I owned a pool store I'd print and post my daily calibration and control results and explain to people why I know my machine is accurate. I've never seen this though. Perhaps the machines made for pool water testing don't have such a capability??? If that's the case they have proven my point of why I don't trust them. Just my .02 on why I don't bring water there. Thanks
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Let me add that at my local Leslie's, there is a dude who just grabs bottles from a rack and drops them in while hand-swirling the tubes. Lots of variables in this process. He's in a hurry, there are people waiting to buy stuff, if he miscounts or puts in too much, he never goes back. Good guy, nice guy, but he's also alone in a retail store with lots of other stuff going on. My free water test is low priority. I patiently wait, and I watch him test other people's water, too, and the same "quality control" applies.

So not only do you have variability in the set of tests he performs, you have 2 weeks between tests, so you could be way off for prolonged periods, and thus be over- or under- on multiple measures and proposed remedies without realizing it. This introduces two types of errors: you think you're OK but you've really got a problem [spend more $ later, and/or have down time, after you discover a huge issue and have to scramble to remedy it] or 2) you think you've got a problem but you're really OK [spend unnecessary $ now].

One of the key advantages to testing yourself is that you control the frequency (daily, weekly) and after you get comfortable with repeating the tests, your own samples/processes are done more consistently, and the increase in data points are more reliable than any single test. If you get a result that is way out of range, you can re-test to confirm before adding expensive chemicals. Even then, you can add say 2/3 of the indicated chemical, wait a few hours, and re-test again, to get a better sense for how much the new ingredient is driving the result.

In the end, it's all sample data. So more frequent samples are better than less frequent. More accurate/consistent samples are better than less accurate/consistent samples.
 
I Received my TF-100 kit, speedstir, etc. today. However, due to other commitments this evening, I won't be able to conduct any testing until tomorrow. I hope the learning curve on these specific tests is quick...it seems like the CYA one is the most difficult/cumbersome.

In regards to the OCLT, do I need to run my filter/pump overnight? Currently my pump runs 12hrs./day (typical during summer months) and is currently programed from 10 a.m. - 10 p.m. So, can I just measure/test for FC (shortly after 10pm when the pump is off) and then test for FC the following a.m. prior to 10 a.m and sunlight hitting the pool?

Since adding 3 additional lbs. of "Punch" shock on 8/25, I've added approx. 3 gallons of 8.25% Clorox Bleach and I've upped the SWG from 60-75%. The water remains sparkling clear.

Thanks!
 

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nv269 said:
I stopped the SWG for two days and now it shows 2.8, as far as my CYA still nothing, what brand of CYA do you guys recommend, i don't want to buy leslies anymore. Thank you.
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I'm far from the expert, but I believe CYA is CYA and brand is of insignificance. If you don't want to use Leslie's brand, use another pool supply store in your area...or check with Walmart, Lowes or Home Depot. As the season is winding down here on the East coast, the seasonal stores may not be carrying it much longer as their stock supply will run out and they won't restock any until spring again.

- - - Updated - - -

kcindc said:
The pump should be running during the oclt. Ask any questions that come up when you are running your first set of results.


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Okay, thanks...and thanks!
 
kcindc said:
The pump should be running during the oclt. Ask any questions that come up when you are running your first set of results.


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If I'm running the pump during the overnight for the OCLT, I need to turn off my SWG, correct? And, if so, how long after I turn off the SWG do I have to wait before taking that first/evening's FC test sample?

Thanks!
 
Make sure to do the CYA test in the full sun, back to the sun, hold vial at waist level with two fingers... sounds a little crazy, but the test is very light sensitive. Anything between numbers should be rounded up to the next highest number.
 
I ran a test today, I'm not sure how accurate these numbers are as it was my first time doing this. I ran subsequent tests on FC, CC, CYA & CH within a few minutes of each other. (From additional reading, I guess I needed to take additional tests at a minimum of 1 hr. from the previous). I'll attempt to do additional testing tomorrow.

The basic 5 drops of solution (blue plastic box; K-1000) for Chlorine and PH revealed a chlorine color that turned ORANGE, like Orange Crush orange! The PH came in around 7.4-7.5.

FC came in at 22 ppm (44 drops of R-0871 X 0.5) Now, when I added the 1 heaping scoop of the R-0870 powder and swirled/mixed, the solution was incredibly pink, like a redish/fushia pink. After 44 drops the solution still had a faint pale pink hue to it versus one of "completely" clear.

In regards to CC, adding 5 drops of the R-0003 to the solution kept the color the same, a faint pale pink, it didn't get any pinker. So, thinking my CC is 0.0?

Due to my lack of confidence, I immediately took another pool sample. I did the same thing regards to FC, but kept adding drops past 44 to see if the faint pale pink would go to "completely" clear. I stopped at 60 drops (which would be 30 ppm) as I didn't see any notable color difference than the 44 drops. I also added 5 drops of the R-0003 solution to the 60 drop vile, and the color stayed the same...as it did at the 44 drop mark.

I performed two consecutive CYA tests (outdoors with back to sun) and both times I came up with 70.

I performed two consecutive CH tests...my readings came in at 450 & 425 respectively. I conducted the second test because all of my pool store tests to date have never displayed a reading exceeding 300. So, I think my test results for CH are not accurate...but I don't know.

TA tested in at 90 ppm.
 
The ph test is unreliable when your Fc is above 10.

You should do the oclt to make sure nothing is growing. If you pass the oclt you need to turn off your swg for a few days and let your Fc drift down.


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kcindc said:
The ph test is unreliable when your Fc is above 10.

You should do the oclt to make sure nothing is growing. If you pass the oclt you need to turn off your swg for a few days and let your Fc drift down.


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Okay. I just turned off SWG, I'll go out around 11 p.m. to get a sample and do the FC test. Then in the a.m. (before direct sunlight hits the pool...which will be around 9:30 a.m.) I'll take another sample and run the FC again.

I trust the kit... :)

Thanks!
 

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