SWG measuring low salt

[Drew80]

We got a big rain (dilution) and afterward my SWG was measuring 2200. It was at 2700 before the rain. Thought that drop was a little drastic for a 3" rain, but I added a whole bag of salt anyway since it was a little low before the rain. Let everything run overnight and it's still registering at 2200, so I'm getting no chlorine generation.

SWGs are a black box to me, so I have no idea how to debug this. What should I do?

 

[Newdude]

You can't argue with the SWG reading, even when you know better. They use a conductivity test to determine salinity instead of a chemical test, and it varies with temperature so it's less accurate.

Your K1766 will let you know if the sensor is at least close, or may be malfunctioning. Normally the no questions asked bag of salt fixes it. Test and see if you need another bag, or if there is something going on with the sensor.

 

[Drew80]

I don't have a K1766, just some crappy test strips that don't seem to work. Looks like I'm going shopping.

 

[Newdude]

The pool store, test strips and the SWG are always all fighting for least accurate like its some kinda prize.

Keep us posted once you have better results.

 

[Drew80]

it's SO true. My K1766 is on the way. I'll update this in a couple days.

 

[Drew80]

@Newdude I just measured with the drop test. It took 30 drops, which means my salt is 6000? That makes no sense to me, but that's what it measured.

 

[Newdude]

Try it again with 10ml of pool water.

 

[Drew80]

That's what I did

 

[jark87]

That's what I did

If I’m not mistaken, I think Newdude was referring to the somewhat confusing instructions with the K1766. I think they say something like “fill the 25ml tube to the 10ml mark.” A lot of people just glance at them and then fill to 25ml.

 

[Drew80]

Yeah, I was confused by that at first, but I did the test with 10mL

 

[Newdude]

OK, I was rooting for you to have screwed up the test. I am the treasurer of that club and we meet on the 3rd Tuesday of each month.

Instead, the drop test is telling us the sensor is failing. Let's page @JamesW who should know T-cells or who else to tag. Hang tight.

Had you screwed up the test, you'd be off by a factor of 2.5 and the salinity would have been 2400, the cell would be more or less right, and $10 in salt would have fixed you right up.

 

[jark87]

I don’t know anything about your cell, but mine has sensors that I can clean. I had the same problem - reading was so low, I was getting an error and no chlorine was being produced. Before replacing anything, I cleaned the sensors with rubbing alcohol and they started reading correctly. Maybe give that a try.

Stabs in the dark like that rarely work for me. Should have bought a lottery ticket that day.

 

[JamesW]

Go to the diagnostic screen, note the readings and then press the + button to reverse the polarity.

When the new numbers appear, see what they are.

Then, press + again and note the new readings.

How old is the cell?

What are the first 7 of the cell serial number?

 

[Drew80]

@JamesW

First reading: -29.28V -2.22A
Second reading: +28.48V +3.59A

First 7 of serial is 1E20038

Cell is just over a year old. Bought in August 2021.

 

[JamesW]

Looks like a bad cell.

Did you check for scale and clean if necessary?

Is it a genuine Hayward bought from an authorized dealer?

The cell has a 1 year warranty, so it looks like you are out of luck.

You should make sure to get a 3 year warranty on any new cell.