Salt testers

We run a salt system pool and at the moment want to test the salt levels. We have tries strips in the past, but they don't seem very accurate and degrade very quickly. We were thinking of buying a testing machine, but one that doesn't cost an arm and a leg. Has anyone tried a refractometer type? I was looking at the general description on Amazon and I'm not sure if they are accurate enough.

Yes Wendy you are probably correct on the pricing side, The ones I sell have the calibration liquid and are adjustable to correct any error but not at the low cost end which is why the titration testers are better sellers, they are accurate and once the kit is purchased the refills are inexpensive.

What chlorinator do you have? The older versions used conventional power supplies, these were not energy efficient but were long lived. Modern units often have switch mode power supplies, these use less power but switch mode power supplies do not tend to have the longevity.

We actually had the plates out to check, but they were very clean. The salt machine we have changes polarity every so often, which keeps the plates clean. No idea why it wasn't working before, but it seems to be OK now, thanks.

Regarding the tester, I had a good look at all the testers available on Amazon, which ranged from about 15€ to 150€. The one I got from Cash Piscine cost 30€ and is exactly the same as others costing 60€ and more, manufacured in China in a blue box. I think one would probably have to pay at the top end to get something made in Europe.

Thanks everyone!

Vinegar is good as a descaler, used in plenty of kettles etc as is lemon juice or any other acid, hydrochloric is fine also but not used full strength.

It was the tester Wendy was talking about calibrating not the chlorinator in this case.

€800 for a cell? what cell was it

Sorry Gerrard, welcome to the pool group, forgot my manners there, in rush this morning.

I would recommend someone like AquaPhil - Mr Philippe Rodriguez 06 14 71 57 76. He's an expert on salt water systems and can re-calibrate your machine for you. It may be the 'cell plates' need to be replaced or stripped of limescale. I had a problem 2 years ago and after testing all the variables realised that the cell plates needed replacing. I called him in as I didn't want to spend €800 unless I had an expert second opinion. He confirmed my diagnosis and his call-out and the cost of replacing the spare part was no more expensive than buying it myself and not being certain. If you're using acid to clear the cell plates of limescale, can I suggest using industrial vinegar (acetic acid) rather than the hydrochloric acid originally suggested to me.

Yes Cash Piscine and the others seem to be able to obtain some items at incredibly low prices but I do wonder about the quality. Normally the electronic testers have a small calibration screw somewhere and you require a liquid standard to set them up. The ones sold on Amazon that you linked to are too cheap, sometimes this is aquarium equipment not meant for chlorinated pool use so can also be short lived.

Glad your chlorinator has woken up, they are not cheap either, if you have hard water this can scale up the cell plates although the units are often self cleaning these days by virtue of reversing the power to aid self cleaning it only works to a point. Manual cleaning in acid also shortens the cell life.

Thanks, John. I agree with what you say. The problem was that the salt machine did not seem to be working, despite chucking in extra salt, but eventually after doing a lot of cleaning and running the machine it seems to have clicked in. We did eventually buy a tester from Cash Piscine, but impossible to calibrate, so couldn't recommend.

Hi Wendy,

Salt levels don't require the same kind of accuracy as the other water chemicals which is why a Dip strip can work if they are from a reasonable company but yes they do degrade once opened like the other Dip strips.

The problem with refractometer is your water must be clean to avoid interference, not saying you can't use them as they are accurate in the refractory index and so is a brewers specific gravity tester.

The digital salinity ones use conductivity and then there is the titration tests kits all accurate enough for salt. 3500ppm +/- 100ppm won't make much difference, having enough so the power supply isn't over working to produce chlorine is all that's needed.