Don't trust Salt Strip Testers - Use the Taylor drop test

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That is a pretty bold statement when many members use the strips without issue ... maybe you got a bad batch?

I have not used them but do have the drop kit which I like for repeatability.
 
I use the test strips as a "reality check" to the sensor on my EasyTouch that seems to not register accurately when water is below 70 degrees (which is always the case when we open in the spring). I don't find them to be precise, but they are accurate on an order of magnitude basis (+/- 200 -300ppm). That's good enough for my purposes.
 
I've used the AquaChek strips and they work for me. I even tested them on water samples with preset salt concentrations (800ppm, 1000ppm and 5000ppm). In all three cases the test strips got with 300ppm of the correct value (read low on all three samples).

I'm curious, what are you basing your assertion on? What is your independent control sample that tells you the strips don't work?

One thing about the strips that is annoying is the directions on the bottle don't match the directions on the package insert. Also, the strips MUST ONLY BE SUBMERGED IN 1" of a water sample not fully submerged or dunked in a pool. I typically use an old test vial, fill it with an 1" of pool water and drop the strip in. You then have to wait 4 mins for the results. As well, you have to match the peak of the white strip to a number on the strip and then look that number up on the side of the bottle to get your sample ppm value. Every bottle has a different calibration scale and so each batch of strips are bottle specific. Also, the strips MUST be kept in a cool dry place with the moisture absorber pillow pack in the bottle. Any exposure to humidity will ruin the strips.


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DogsHouse_MyPool said:
I am curious. Do people on the form question and dismiss Taylor reagent testing due to bad batches with the regularity that they do for test strips?
Click to expand...

One reason why reagents are superior to strips is that the color indicator solutions are separate from the the titration reagents. It is very hard to get a bad batch of liquid reagents.

In test strips, all if the chemicals have to be impregnated onto a little white tab of paper or cotton. Thus the indicator chemical is in direct contact with any reagent needed to cause the reaction. This leads test strips to being much more vulnerable to variations in chemical concentrations and partial reactions. Test strips are inferior to chemical reagents and more subject to environmental degradation than bottled liquids.

In most, if not all municipalities, test strips are not acceptable methods for testing water quality.


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Two thoughts for this thread.....

For a member with less than 200 posts, links are not allowed within any part of the post, sig, text, etc. Lot's of reason's why but they are not allowed.

Secondly, While I don't have an SWG I would likely use the Strips simply because it makes very little difference in the big schemem of things. If your SWG is happy with the salt level and it is producing chlorine as a result, I see no real reason for any further precision.


Some pool owners do (want more precision) and there is certainly nothing wrong with endorsing precision on a forum that begins and ends with accurate testing. I really see it as a personal approach as to how you intend to manage your pool water. TFPC does not teach you the ONLY way to manage your water, it teaches you to understand How to manage your water and then involves you choosing your own path that works well for you.
 
Duraleigh,

+1 on your post!!!!

As an AquaChek strip user, I do plan to finish my bottle and then make the switch to Taylor drops (and get a speedstir because I'm tired of swirling solutions by hand). My reasons are not because I think strips are bad, I just prefer the simplicity of counting drops.

As you said so eloquently, "to each his own"


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I bought a bottle of strips but when my 2 SWCG came in, I found they each came with a bottle. So, I had 3 bottles.

To start my salt water pool, I put in 720 lbs of salt. The SWCG's were both saying "lo" but I decided to give them time to get to steady state. After 24 hours, one read "lo" and the other "normal". They were at opposite ends of the pool, each near a return, as instructed. I tested with the strips. I tested many times from strips from each bottle. I did not put them in 1" of water (The bottle didn't say to do that. I checked and now see it says "For complete instructions, see package insert".) The strips were put in the water for 10 minutes & I got a reading of 2200 ppm. So I go buy more salt and dumped in more 320 lbs, waited 24 hours and then got a then reading of 2600 ppm. I tested many times from strips from each bottle. Now one SWCG read "hi" and the other "normal". I think they're not calibrated properly.

Frantic, I found the Taylor kit and when it arrived, my salt level was 4600 ppm! Too high! So, I'm going to have to dump some water & replace but at least now I can get an accurate reading.

Since I used strips from all 3 bottles, I don't think I got a bad batch. I'll try testing in 1" of water but it seems that would be printed on the bottle if was that important. I mean who reads the inserts? ;) But out of curiosity I'll do it to see if that makes any difference. But I'll stick with the Taylor Salt testing kit, thank you!

The good news is that after running the SWCG for 7 days, my chlorine was at 7.4 so now I've put the SWCG's on 50% output. Other than the strips messing me up, I am very happy with the SWCG set up...

As for not being allowed to post links? Never heard that rule... I don't see the harm showing people where to get test kits that I like.

Thanks for your input. Have a swimming day.
 
The mistake was submerging the strips in the water, so most likely the strips were just fine to begin with. Lesson learned and file that one away for the future. That said, I like the Taylor test used with a SpeedStir. Just remember all the tests are +- 400.
 

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+1 to cubgirl's post.

I bought test strips ahead of my swg and now I have sets of strips. I saw the aquarite video and only used 1" sample for test strip before I got the swg running. Test strip reading after startup was 2930. Hayward AquaRite/SwimPure panel reads 3000-3100 ppm salt. My test strip reading the following week said 2490. Now we had a lot of rain that week, and Im sure I lost maybe 2-3" water due to overflow. That would equate to a potential drop of 4-6% in my pool compared to the 15% measured by the strips. I can understand that all tests are +/- 400 ppm, but I would think that even test strips are more consistent than that within the same batch/bottle. I would not expect one strip to be +200 while another is -200. I would hope the mfg has better quality control than that.

I too didn't know about the 200 post requirement to for embedding links. I guess I better read the rules.

I have not added salt as I am generating CL, but I am now questioning my strips, since they all came out of the same bottle. I am considering what is said in the forum and wonder if there is more I need to know about the chemistry behind the swg system than keeping my salt level in range.
 
Once the salt level has been established and the SWG has been up and running the saying we like to go by is, if the SWG is happily making chlorine then go by the salt reading the SWG is saying it is and leave it alone. When the SWG is having problems with the salt level, then it is time to verify the salt level before you start to add salt or drain water to lower the salt level.
 
I recently had to drain and refill (had a leak which caused some wrinkles over the winter, had to drain most of the water to get the wrinkles out). I re-added salt according to Pool Math. I tested using strips - one strip from a pack that expired two years ago, and one that was not expired yet. Both reported the expected amount of salt. The expired one was a little hard to read, but still seemed accurate.
 
chem geek said:
I use a 25 ml sample size with the Taylor drop-based salt test for a resolution of 80 ppm, but I'm measuring lower non-SWCG salt levels. The resolution using the 10 ml sample size recommended in the test is 200 ppm.
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Is your salt for feel? What level do you target that you want 80ppm resolution? I seem to remember that around 2000ppm was recommended when using salt just for feel, and surely ~10% resolution is sufficient enough for salt for feel?
 
No, I don't add salt for the feel. I just wanted to know the salt level in my pool to get an idea of the needed water dilution over time (multiple years). It usually hovers in the 1000-1600 ppm range which is apparently the steady-state from my chlorine additions and winter rain overflow for dilution. I don't currently do any additional dilution. A 200 ppm resolution would probably be fine -- I'm just a chem geek so like to get more precise numbers when possible, especially to see more subtle trends.
 
ping said:
Once the salt level has been established and the SWG has been up and running the saying we like to go by is, if the SWG is happily making chlorine then go by the salt reading the SWG is saying it is and leave it alone. When the SWG is having problems with the salt level, then it is time to verify the salt level before you start to add salt or drain water to lower the salt level.
Click to expand...

-- Full disclosure - I am a brand-new pool owner with limited testing under my belt --

That being said, the theory above is what I have chosen to go with. My pump/control panel measures salt content for my SWG. I bought a bottle of test strips when I bought the TF-100. I tested with one of the strips (in 1" of water) vs. what the control panel said, just to see how close the 2 were.

The control panel said 3800. The strip was reading 3000-3100. I may look into one of the reagent kits when I run out of strips, just from an cost saving standpoint. The strips come with 10 tests. Based on the Amazon reviews, it looks like you may get as many as 100 tests out of the reagent kit for less than twice the price of the strips.

That being said, as long as my control panel says I am staying within the manufacturer's recommendations and my SWG is adequately producing chlorine, I am not overly concerned about knowing the precise number.
 
I think several things are important to remember with SWGs and Salt levels -

1. The readings from SWGs, strips & reagents are all ~ +\- 300 to 400 ppm. If you want better than that, you'd have to pay for more expensive testing.

2. The output reading from your SWG is nothing more than fancy resistance meter - it's correlating the conductivity of your water solution to a salt ppm value. Many things aside from salt concentration can affect waters conductivity (pH, temperature, other dissolved ions, etc) so the correlation will have a wide margin of error.

3. The SWCG reaction of turning a sodium chloride solution into FC is very robust and can operate over a wide range of salt concentrations. Using the typical value of 3400ppm simply allows the drive electronics for the cell to operate at reasonable current and voltage levels without the need for more complicated electronics. It also allows the pool owner to put a reasonable amount of salt in the water without feeling like you're swimming in the Dead Sea.

So I too ascribe to the above philosophy - if you've calculated the amount of salt you needed to add and your SWG is happy, no need to get too exact with your test values.




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