Salt water pool tester

[merijn]

Hi All,

I have converted my normal pool to a salt water pool.

I'm looking for a salt water tester (test strips) to check my salt content in my pool.

I asked some of the pool companies and they don't have them as according to them i don't have to test it as the chlorinator should take care of it.

Rather then relying on the machine i would like to test the water myself once in a while.

Does anybody knows where i buy salt test strips? preferable in Phuket otherwise online.

[luk AJ]

If it is only salt content you want to test you can buy a refractometer, this is very accurate, no chemicals needed no batteries. Works on the principle of breaking light. Just rinse with fresh water after use.

[TheCruncher]

Not sure if strips even exist, but you can buy a digital salinity tester on Ebay at a fraction of the price you can buy it in a Thai poolshop, and it will be the exact same tester.

I use a TDS meter for it, but you should deduct the TDS from your water source from the reading.

A pure salinity meter is more correct though.

http://www.ebay.com/sch/i.html?_odkw=salt+tester&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xpool+salinity+tester.TRS0&_nkw=pool+salinity+tester&_sacat=0

[IMHO]

For salinity testing, I bought a digital TDS (Total Dissolved Solids) tester for about 1000 Baht - almost a no brainer over test strips/dips, IMHO.

That said, most salt water chlorinators will warn you when the salinity is too low or high, and you'll soon figure out how many bags (or portion of bags) you'll need to add when the low salt warning goes off....

Edit: this is the one I use: http://www.amazon.com/Dr-Meter-TDS-3C-Quality-Resolution-Accuracy/dp/B00KSTZGNE

And I also use the same brand (Dr Meter) digital pH tester. Actually the cost wasn't 1000 Baht - it was about 2000 Baht all-in for the two testers.

Edited December 22, 2015 by IMHO

[luk AJ]

[sappersrest]

Digital testers are ok but do need calibrating and (can be way out )with control solutions every so often I calibrate my tds meter about once ever 6 months and it cost about 5000 baht in the uk.

[sappersrest]

Try these

http://www.aquachek.com/pool-spa-owners/aquachek-salt-system-test-kit/

[Chuckles78]

I bought these...

[Chuckles78]

If it is only salt content you want to test you can buy a refractometer, this is very accurate, no chemicals needed no batteries. Works on the principle of breaking light. Just rinse with fresh water after use.

I had to look this up, very interesting. I've seen some friends in a vinyard use a similar tool to test the sugar content (i think it was) of their grapes.

Anyhow, i found a pic of a refractometer. I'll get one after i run out of strips.

[bazza40]

If it is only salt content you want to test you can buy a refractometer, this is very accurate, no chemicals needed no batteries. Works on the principle of breaking light. Just rinse with fresh water after use.

At the recommended level of 3000 - 7000 mg/L salt ( 0.3 -0.7% ), a refractometer is about as accurate as tossing a coin or using a dartboard. Apart from the fact the best working range for these instruments is 2 - 10% concentration, refractometers will give wildly different results depending on the ambient temperature, which is why laboratory refractometers have temperature controllers to +/- 0.1 degrees C.

Probably the best cheap instrument for measuring salt concentration is a conductivity meter, which can be calibrated against solutions of known salt concentration.

[luk AJ]

If it is only salt content you want to test you can buy a refractometer, this is very accurate, no chemicals needed no batteries. Works on the principle of breaking light. Just rinse with fresh water after use.

At the recommended level of 3000 - 7000 mg/L salt ( 0.3 -0.7% ), a refractometer is about as accurate as tossing a coin or using a dartboard. Apart from the fact the best working range for these instruments is 2 - 10% concentration, refractometers will give wildly different results depending on the ambient temperature, which is why laboratory refractometers have temperature controllers to +/- 0.1 degrees C.

Probably the best cheap instrument for measuring salt concentration is a conductivity meter, which can be calibrated against solutions of known salt concentration.

The OP wanted a salinity meter for a salt water pool, so I have no idea why you come up with salinity concentrations between 0.3 a 0.7%. I use refractometers in my job for the last 20 years without any problem.

[IMHO]

If it is only salt content you want to test you can buy a refractometer, this is very accurate, no chemicals needed no batteries. Works on the principle of breaking light. Just rinse with fresh water after use.

At the recommended level of 3000 - 7000 mg/L salt ( 0.3 -0.7% ), a refractometer is about as accurate as tossing a coin or using a dartboard. Apart from the fact the best working range for these instruments is 2 - 10% concentration, refractometers will give wildly different results depending on the ambient temperature, which is why laboratory refractometers have temperature controllers to +/- 0.1 degrees C.

Probably the best cheap instrument for measuring salt concentration is a conductivity meter, which can be calibrated against solutions of known salt concentration.

The OP wanted a salinity meter for a salt water pool, so I have no idea why you come up with salinity concentrations between 0.3 a 0.7%. I use refractometers in my job for the last 20 years without any problem.

I think what he might be trying to point out is the refractometer in Chuckles78's picture doesn't have enough resolution to be useful for a pool.

My chlorinator specs require a TDS/Salinity of 5,000 PPM +/- 2,000 PPM - that equates to 0.5% +/- 0.2% salt. These levels would barely register on the device shown.

Edited January 2, 2016 by IMHO

[IMHO]

If it is only salt content you want to test you can buy a refractometer, this is very accurate, no chemicals needed no batteries. Works on the principle of breaking light. Just rinse with fresh water after use.

I had to look this up, very interesting. I've seen some friends in a vinyard use a similar tool to test the sugar content (i think it was) of their grapes.

Anyhow, i found a pic of a refractometer. I'll get one after i run out of strips.

ImageUploadedByThaivisa Connect1451079622.779271.jpg

You'll need one with a range of 0 to 1%, not 0 to 10% - if such a thing exists.

TDS meters, are cheap, don't drift, and produce accurate numbers though.

Edited January 2, 2016 by IMHO

[sappersrest]

Tds meters do drift especially if hey are cheap (expect to pay around 4000-5000 baht for a reasonable one ) and require recalibrating ,it should have a small adjusting screw on the side you do need a control solution to this.

Don't forget there are salts of varying sorts sulphates, sulphides from the pool chemicals we use i.e. soda ash , acids etc etc.

These over a period of time could add as much as 1500 ppm to your readings.

Still we are not into nuclear physics , so in real terms ,should not matter to much in the short term, but something to keep an eye on .

[luk AJ]

Tds meters do drift especially if hey are cheap (expect to pay around 4000-5000 baht for a reasonable one ) and require recalibrating ,it should have a small adjusting screw on the side you do need a control solution to this.

Don't forget there are salts of varying sorts sulphates, sulphides from the pool chemicals we use i.e. soda ash , acids etc etc.

These over a period of time could add as much as 1500 ppm to your readings.

Still we are not into nuclear physics , so in real terms ,should not matter to much in the short term, but something to keep an eye on .

If you scroll back, you will find salinity meters posted by me. You can have them in different ranges. For the purpose of the OP I suggest range 0 to 10%. Indeed these have a small screw on the bottom, for home use best to put tap water on the lens and check if reading gives zero. If not adjust with screw.

[TheCruncher]

Tds meters do drift especially if hey are cheap (expect to pay around 4000-5000 baht for a reasonable one ) and require recalibrating ,it should have a small adjusting screw on the side you do need a control solution to this.

Don't forget there are salts of varying sorts sulphates, sulphides from the pool chemicals we use i.e. soda ash , acids etc etc.

These over a period of time could add as much as 1500 ppm to your readings.

Still we are not into nuclear physics , so in real terms ,should not matter to much in the short term, but something to keep an eye on .

If you scroll back, you will find salinity meters posted by me. You can have them in different ranges. For the purpose of the OP I suggest range 0 to 10%. Indeed these have a small screw on the bottom, for home use best to put tap water on the lens and check if reading gives zero. If not adjust with screw.

Tap water doesn't have a reading of zero, even when it is reversed osmosis. My tap water, though it is from a well and goes through a water softener and sediment filter, has a reading above 500.

Edit : Apologies as I mistook your salinity readings for TDS readings.Tap water will indeed have a reading near zero for salinity.

Edited January 3, 2016 by TheCruncher

[bazza40]

As a scientist, it's appalling to read posters who say a particular instrument is accurate. They don't understand the concept.

Let's say we have an instrument that gives readings of 3950 mg/l, 4000 mg/L, and 4050 mg/l, average 4000 mg/L Does this instrument give reproducible results? Yes it does. Does it give accurate readings? If the true value is 5000 mg/L, no it doesn't.

I have lost count of the number of times any instrument which gives reproducible results is described as accurate.

[bazza40]

If it is only salt content you want to test you can buy a refractometer, this is very accurate, no chemicals needed no batteries. Works on the principle of breaking light. Just rinse with fresh water after use.

At the recommended level of 3000 - 7000 mg/L salt ( 0.3 -0.7% ), a refractometer is about as accurate as tossing a coin or using a dartboard. Apart from the fact the best working range for these instruments is 2 - 10% concentration, refractometers will give wildly different results depending on the ambient temperature, which is why laboratory refractometers have temperature controllers to +/- 0.1 degrees C.

Probably the best cheap instrument for measuring salt concentration is a conductivity meter, which can be calibrated against solutions of known salt concentration.

The OP wanted a salinity meter for a salt water pool, so I have no idea why you come up with salinity concentrations between 0.3 a 0.7%. I use refractometers in my job for the last 20 years without any problem.

0.3 - 0.7% salt is the recommended range for a salt water pool. Refractometers may be quite appropriate for some applications; however, since you don't say what your job was, I can't say if their use was appropriate.

During my scientific career, I made myself quite unpopular by demonstrating the application of various instruments to inappropriate matrices or measurement ranges generated data which was garbage.

Edited January 6, 2016 by bazza40

[IMHO]

Tds meters do drift especially if hey are cheap (expect to pay around 4000-5000 baht for a reasonable one ) and require recalibrating ,it should have a small adjusting screw on the side you do need a control solution to this.

Don't forget there are salts of varying sorts sulphates, sulphides from the pool chemicals we use i.e. soda ash , acids etc etc.

These over a period of time could add as much as 1500 ppm to your readings.

Still we are not into nuclear physics , so in real terms ,should not matter to much in the short term, but something to keep an eye on .

You're probably right, but given the fairly wide operating range of most chlorinators, and that's there's really no bad side effects to running salt levels "a little too rich" (other than a salty taste), you don't need pin-point accuracy - like you do on other chems you're adding

Most good chlorinators monitor themselves - all you need to do is add salt when the "low salt" lamp illuminates, and try not to overdo it so the "excessive salt" lamp illuminates. It doesn't take too many cycles for you to get a feel for how many bags (or part thereof) you need to add when the low salt lamp comes on

Edited January 7, 2016 by IMHO

[BryanD]

Hi

As of a couple weeks ago, I have myself a nice new in-ground salt water pool. It has the AQR-9 chlorine generator with the AQR control panel. I did as the instructions stated on the control panel - dumped in the salt and let the filter run for 24 hours, then turned on the generator and let it run for 24 hours to get accurate salt PPM. It's been a couple of days, and I've tested the chemicals with a test strip. The chlorine reading according to the test strip is 0. The AQR indicates that the cell is generating chlorine. After the first test strip indicated no chlorine, I upped the desired output % to 75%. The next day I retested with another test strip and it still shows 0 chlorine. Does this indicate something is wrong? The test strip does seem to be reading the other levels correctly (pH, total alkalinity, and stabilizer). I had a look at sties like these and wikipedia.. But i am still confused.. 

Any Help would be great-full..

[sappersrest]

Did you put in the correct amount of salt, on start up what is your pool volume?(US galls and imperial galls are different)

On initial fill was the pool super chlorinated?

if so you could be bleaching out the reagent on the test strip.

Check the date on the cap of the test strip it may be out of date.

It may be possible to check the current draw on the cell at various settings. 

BUT ONLY IF YOU ARE COMPETENT TO DO SO

 

Is the cell configured correctly on initial commissioning.?

Is the flow switch working correctly.?

Are all jumpers in the correct configuration?

Take a sample to your local pool store to test.

 

Do you have the user/installation manual?

[SantiSuk]

In a word - yes. 95% likely that your salt test strips are rubbish (they are generally a hopelessly reliable way of reading salt IMO having tried a couple of vesrions). I suspect you got old stock form the shop.

 

What about chlorine. Are you not going to test chlorine levels? Get a cheap two bottle CL and pH test kit for about 550 baht at one of the Thai pool online shops or possibly Lazada (Thai Amazon me too online retailer) or Amazon. All these avenues will get stuff to you within a few working days IME. The bottle testers are pretty difficult to read - ie colour match - on CL, but they will at least tell you whether your CL is 0, less than 1 (weak straw colour) or more than 2 (strong yellow if you tip the output into a white enamel basin). [pH is much easier to read relatively accurately between 6.8 and 7.6 IME].

 

Alternatively get a TDS digital meter - covered above in depth but I would add that I just bought one for less than 200 baht on eBay - yes seriously. It will probably fail within 6 months (my last one also very similar and also produced cheaply in China but costing ore like 2000 baht failed within a couple of years) but at that price who can complain - it arrived within about 3 weeks of buying on UK eBay site and it is reasonably accurate at the moment (based on my use of a previous now defunct meter plus warning lights on the generator plus experience of my own pool and records of salt consumption plus knowledge of what salt levels taste like!). As Sapperset points out earlier in this thread (haven't read the posting I see he has made a couple of minutes ago) they need to be more expensive than this and calibrated but I believe they can be used for a short while with reasonable accuracy as factory calibrated out of the box if all you are looking for is to know that salt ppm is somewhere around or over 3,000 ppm or 4,000 ppm whatever your chlorinator manual specifies as the target. You do however need to be able to test your source water TDS to subtract that from the total TDS reading of your pool. That requires a certain amount of guesswork as to the mix of your pool water between rainfall and your ground or piped water source - assuming 50% of each is not too wildly amiss at this time of year post rainy season IME where I am. So salt level = TDS of pool sample less (half TDS of rainfall pluss half TDS of other source). Where I am rainfall has a TDS of roughly between 150 and 350 and my village water from a deep well has a TDS of around 1300 plus or minus 100 (but I measured an outlier of 2,100 once). [The TDS of my 30m deep well water is over 2,500, so I turned off my auto feed and manually top up with piped village water for now!]

 

Complicated? Yes a little but have you seen the price of proper pro or semi pro salt (as opposed to TDS) meters? You can't seem to buy one from Thai pool shops anyway. One of the big ones told me they can't find a reliable one to put in stock (at any price a Thai retail customer would be prepared to pay I presume they meant!). I'm not prepared to 15,000 baht to be a guinea pig for a real proper one from OZ or the US when there is also the Thai mail (usually v good IME, but sods law would prevail as soon as I shelled out that kind of money).

[SantiSuk]

Meant to add the web address for the super-cheap TDS meter.

 

http://www.ebay.co.uk/itm/TDS3-TEMP-PPM-TDS-Meter-Tester-Pen-Stick-Quality-Pool-Purity-Monitoring-NEW-/272400981654?hash=item3f6c5d1e96:g:kQ8AAOSwNRdX85tr

[Mike09]

Hi Merijn,

 

I don't use test strips on salt water pool.
I bought this amazing salt water test kit k-1766 by taylor technologies and it worked well!

I think we bought it from an online pool company.. here's the link in case you want to check it out: https://pstpoolsupplies.com/taylor-technologies-k-1766-drop-test-sodium-chloride-salt-water-200-ppm/

 

Youtube is a great source for me to easily figure out how to do the test.

Here's what I watched which I hope will help you too:  :)

 

[Crossy]

I just bought a cheap TDS meter and calibrate it by dissolving 4g of salt in 1L of tap water (the same source I use to fill the pool).

 

Whatever the meter reads is what I take as the nominal for my chlorinator (40kg per 10,000L according to the instructions). Seems to work ok and the chlorinator hasn't complained.