Testing Salt

[sonflower]

Does anyone use a salt tester they could recommend?

Our Aqua-Rite seems flakey.

Sunday it sd 2600 so I put 2 bags of salt in and made a note to ck the salt level in the morning.

Monday's reading sd 3500 on salt.

I am not trusting my AquaRite reading right now.

Thanks in advance.

[sonflower]

Plz disregard. I got my answer in another forum. Taylor k 1766 is it.

[polyvue]

Does anyone use a salt tester they could recommend?

Our Aqua-Rite seems flakey.

Sunday it sd 2600 so I put 2 bags of salt in and made a note to ck the salt level in the morning.

Monday's reading sd 3500 on salt.

I am not trusting my AquaRite reading right now.

Thanks in advance.

Yes, I use the Taylor K-1766 chloride test to verify the salt level in my pool (use Goldline's Aqua T-Cell SWG) but the salt level reported by the cell / controller is the determining factor in the production of chlorine. I've found that it can take as long as 8-10 hours of pumping/filtering to register salt additions. It helps to cycle the unit every few hours (turn it off for a while, then back on) to get a correct reading.

[waterbear]

Does anyone use a salt tester they could recommend?

Our Aqua-Rite seems flakey.

Sunday it sd 2600 so I put 2 bags of salt in and made a note to ck the salt level in the morning.

Monday's reading sd 3500 on salt.

I am not trusting my AquaRite reading right now.

Thanks in advance.

You don't say how big your pool is but 2 40 lb bags of salt will raise 10k gal water about 950 ppm and 2 50 lb bags will raise 10k gal about 1100 ppm so unless your pool is much bigger or smaller than 10K your aquarite is certainly reading in the ballpark since you showed a 900 ppm rise in salt.

I would recommend AquaChek salt strips over the Taylor kit. Both use the same chemistry (silver nitrate reaction to chloride ions) but the AquaChek stips are MUCH less error prone (and the siiver nitrate salt titration is tricky at best). Realize that I am NOT one to recommend test strips for water testing with only two exceptions, AquaChek salt strips and LaMotte Borate strips. Both are more than adequate for the job they are supposed to do. For all other testing I recommend the Taylor K-2006.

[Pool Clown]

This is what i use and have had no problem wondering if it is accurate. It can be calibrated, although i have not had to in months.

[waterbear]

This is what i use and have had no problem wondering if it is accurate. It can be calibrated, although i have not had to in months.

Yes, IF you calibrate it on a REGULAR basis with the standard solution AND you do not use it on water colder than about 70 degrees it is extremely accurate. It is actually one of the better electronic salinity testers out there. (It's a rebranded Oakton.) I have used them when I have had to test many pools (AND have crossed checked them against MyronL meters, which are superior but much more expensive) and it is a dependable unit. Calibration is important. I would calibrate mine weekly.

Realize also that electronic salinity meters are actually measuring conductivity, much like your salt cell does, so they will necessarily produce the same results as a chemical test like the Taylor titration or the AquaChek strips, which are measuring chloride ion concentration. The results should be close and either method is usable

[waterbear]

This is what i use and have had no problem wondering if it is accurate. It can be calibrated, although i have not had to in months.

Yes, IF you calibrate it on a REGULAR basis with the standard solution AND you do not use it on water colder than about 70 degrees it is extremely accurate. It is actually one of the better electronic salinity testers out there. (It's a rebranded Oakton.) I have used them when I have had to test many pools (AND have crossed checked them against MyronL meters, which are superior but much more expensive) and it is a dependable unit. Calibration is important. I would calibrate mine weekly.

Realize also that electronic salinity meters are actually measuring conductivity, much like your salt cell does, so they will necessarily produce the same results as a chemical test like the Taylor titration or the AquaChek strips, which are measuring chloride ion concentration. The results should be close and either method is usable.

For the home pool owner I would recommend the AquaChek strips based on cost, reliability, simplicity, and precision. It's what I use in my own pool (and I do have a meter and a Taylor titration test also!)

[polyvue]

For the home pool owner I would recommend the AquaChek strips based on cost, reliability, simplicity, and precision. It's what I use in my own pool (and I do have a meter and a Taylor titration test also!)

Unfortunately, and for reasons that remain unresolved (but not unexplored), AquaChek salt test strips do not invariably produce accurate results. I found this out last summer when the strips consistently reported 800-1000 ppm higher than my Goldline controller. This saga was related on a pool web site that I don't wish to reference here. I don't claim that the AquaChek titrators aren't viable for most people, most of the time (they worked for me, too, during the first year of pool use), only that they're not fool proof. The results of the Taylor drop test, however, seem right on the money and I would assert that the end-point determination is no more challenging than that of the Calcium Hardness titration, especially when using a 10 mL sample -- the salmon color comes on strongly and quickly. Since the Taylor K-1766 drop test can be had for less than $20 (PoolWeb, excluding shipping) it's certainly within reach of the typical pool owner.

[sonflower]

Thanks for all the great info!

[waterbear]

For the home pool owner I would recommend the AquaChek strips based on cost, reliability, simplicity, and precision. It's what I use in my own pool (and I do have a meter and a Taylor titration test also!)

Unfortunately, and for reasons that remain unresolved (but not unexplored), AquaChek salt test strips do not invariably produce accurate results. I found this out last summer when the strips consistently reported 800-1000 ppm higher than my Goldline controller. This saga was related on a pool web site that I don't wish to reference here. I don't claim that the AquaChek titrators aren't viable for most people, most of the time (they worked for me, too, during the first year of pool use), only that they're not fool proof.

ANY testing method can be unreliable if not carried out in the right way. Meters need to be calibrated or they are useless. Strips and regents do expire and need to be fresh. Titration can be done past the endpoint if done too quickly or not mixed properly! I use all three methods and find the strips are probably the easiest for most people to perform properly BUT they must be fresh and kept DRY! I have seen problems with old strips or ones that have gotten moist but I also have seen many problems with meters and with chromate/silver nitrate titration for chloride ions.

Also remember that meters (EITHER handheld or in your SWG) and chemical tests (both drop and strip) are reading different things. Meters are measuring conductivity of the water and are affected by not just the salt present but by the temperature of the water and all the ionic solids besides salt dissolved, which also have an effect on conductivity. They use an internal conversion table to convert the conductivity to a salt reading so they can give a reading that is "off" if the temperature of the water is "out of range" or if the water has a lower or higher level of dissolved ionic solids than the conversion table is based on.

Chemical tests are measuring the amount of chloride ions in the solution so one would think they provide a more 'accurate' picture of the salt level. However, since the rate of electrolysis is really dependent on the conductivity of the water, there are factors besides chloride ion concentration that come into play in the operation of your SWG (such as temperature!)

Bottom line, go by the reading on your SWG since that is the operative reading as far as the proper operation of your system is concerned! If it is within about 800 ppm to a secondary test then call it a day and don't lose any sleep over it! If it is more than that start looking for problems (for example scale buildup on the cell or very cold water if the SWG is reading much lower than a secondary test.)

[polyvue]

I agree with your conclusion. It's the SWG cell's report that matters for chlorine production.

I'm sure some folks have used expired AquaChek/Hach salt strips or removed the desicant, left them open, etc. but I was able to rule out each of these issues and still had a huge discrepancy to account for. On the Hach website I found a number of reasons provided by the manufacturer (possible interferences) but half of them didn't seem to apply and the others required testing facilities I lacked. My problems with the test strips drove me to start researching TDS constituents, thinking that there was something in the water that was tweaking the salt strips (and causing the same manufacturer's strips to report 6000+ PPM TDS). I have to say that this was not a fruitful pursuit. It's possible, to the degree that anything is possible, that the pool water contained an unusual element that caused both strip tests to read high but I've given up searching for it.

For what it's worth, a few other reg contributors to that forum reported similarly high levels of salt (chloride) when using test strips, much higher than the conductivity measurements of their SWGs would suggest.

[waterbear]

For what it's worth, a few other reg contributors to that forum reported similarly high levels of salt (chloride) when using test strips, much higher than the conductivity measurements of their SWGs would suggest.

I have seen this myself. However, when double checked with a chromate/silver nitrate titration the results have been more in line with the strips (since both are using silver nitrate to test for chloride ions) and not with the conductivity tests. I have also had the experience of hand held meters showing the same ballpark results as the SWG itself while a chemical test shows a much higher value. This is because you are trying to compare apples and oranges (conductivity and cloride ion concentration.) I have also seen this discrepancy to be in the ballpark of 800-1000 ppm (and Goldline even has said on their website before it was redone that their readings could be off by as much as 800 ppm compared to a chemical test.)

Also realize that my experience has not just been with my own pool but also customer's pools.

[polyvue]

For what it's worth, a few other reg contributors to that forum reported similarly high levels of salt (chloride) when using test strips, much higher than the conductivity measurements of their SWGs would suggest.

I have seen this myself. However, when double checked with a chromate/silver nitrate titration the results have been more in line with the strips (since both are using silver nitrate to test for chloride ions) and not with the conductivity tests. I have also had the experience of hand held meters showing the same ballpark results as the SWG itself while a chemical test shows a much higher value. This is because you are trying to compare apples and oranges (conductivity and cloride ion concentration.) I have also seen this discrepancy to be in the ballpark of 800-1000 ppm (and Goldline even has said on their website before it was redone that their readings could be off by as much as 800 ppm compared to a chemical test.)

Also realize that my experience has not just been with my own pool but also customer's pools.

My experience is limited to my own pool and dates back almost 36 months -- beat that!

Everything you say makes sense... but referencing my own vast 4-month comparative sampling (!) I found that once the salt test strips began showing high levels of salt (the SWG reported no change, warm summer water, no calcification or debris in the cell, 2 bottles of test strips purchased a year apart from different sources agreed with each other) the only correlation was between the silver nitrate drop test and the cell. The drop test results were and remain within 100 PPM of what the cell reports. I ran out of salt strips in the fall and didn't continue the comparison but the results of a conductivity test using a salt/tds meter in October were in sync with the cell and the drop tests. Go figure.

If you have some inkling of what may have contributed to this experience I'm all ears.

[chem geek]

My experience with AquaChek White test strips vs. Taylor K-1766 is that for my own pool's salt level in the 1000-1300 ppm range they were reasonably close, but for a neighbor's SWG pool in the 3000-4000 ppm range the AquaChek was reading somewhere around 800 ppm higher than the Taylor test and I repeated these tests several times just to make sure it wasn't me doing something stupid. This was a few years ago and at that time the test strips were nearly new and very dry since I didn't use them regularly and they weren't old. This is just one experience, however, but when we started seeing other reports similar to this my hunch is that the test strips CAN read correctly but sometimes they do not and I don't know why. Obviously, if they get wet or too old then that's a problem, but there were enough reports from people who claimed to be careful (including myself) that I just don't have the same good feeling about them as I do with the Taylor test.

[Pool Clown]

For the home pool owner I would recommend the AquaChek strips based on cost, reliability, simplicity, and precision. It's what I use in my own pool (and I do have a meter and a Taylor titration test also!)

Not me..., I've had to drain/dilute too many pools where the customer was relying on the test strips and put too much salt in. Do all my customers have old strips, and let them get wet? I don't know, would be quite a coincidence though.

You mentioned that you calibrate yours weekly, are you having to really calibrate it every week? Or are you just checking it with the solution? Reason i ask is, I checked mine a month after i got it and had to calibrate it 0.1, since then i check it monthly and haven't had to adjust it. (I have had to change the batteries more than I've needed to calibrate!) Going on three years. If your having to adjust yours every week, i would suggest perhaps yours is having trouble holding a calibration. BTW i also get accurate readings in water < 70 degrees.

[waterbear]

You mentioned that you calibrate yours weekly, are you having to really calibrate it every week? Or are you just checking it with the solution?

I check the calibration with the standard solution. I generally only need to recalibrate about every 6 months or so (and that might be from batteries getting weak). Now the LaMotte meter we had at work for a while would not hold a calibration from week to week but the Oaktons and MyronL's are workhorses!

The Goldline handheld is a rebranded Oakton.

FWIW, My experience with water testing and meters goes back to the 70s (giving away my age), when I was working on a research project in oceanographic physical chemistry on the precipitation of calcium carbonate from seawater and the effect various ions had on it. This is where I got LOT of experience with lab grade pH meters!

As you can see from how often I check the calibration (a habit I picked up from working with pH meters, which need frequent calibration!) I am quite *** about my testing. When I test for salt I usually will do a chemical test and a conductivity test and if possible, compare that to the SWG reading (not all customers have units with readouts). My findings have been that the strips were always 'within spec'. Like I stated before, a discrepancy of 800 ppm is not unusual. I have actually seen more discrepancy with the goldline meter reading low than the strips reading high! Whenever I have compared the strips to the titration I am usually within about 400 ppm, which is certainly within spec. However, YMMV.

Remember, this is a swimming pool and not an analytical lab!

[waterbear]

Not me..., I've had to drain/dilute too many pools where the customer was relying on the test strips and put too much salt in. Do all my customers have old strips, and let them get wet? I don't know, would be quite a coincidence though.

If your customers are anything like mine were the problem is not in the testing but in the fact that they just dump in a bag or two of salt and hope for the best. How many pool owners actually measure the chems they put in their pools? Most just dump and go (at least in my experience!) Ask your customers if they ever use measuring cups or scales for their pool chems. (I use both for the chems I put in my own pool, btw.)