SWG Winter and Cold Water

[jamie1983]

I am getting a low salt message on my pool. During the winter I just use a floater/pucks for chlorine, is there any reason I should add salt now? Or is it okay until I wait for it to warm up.

 

[ping]

Most likely you are getting false readings due to the cold water. Wait until the water warms up and check your salt level then. Do not rely only on the reading you get on the SWG, always test with strips to confirm that the SWG is correct before adding salt. Too many times the sensors or cells are failing and the salt level is fine where it is at.

 

[mas985]

Do not rely only on the reading you get on the SWG, always test with strips to confirm that the SWG is correct before adding salt.

I would agree with this only under certain circumstances. Normally, you should always rely upon what the SWG is telling you because that is what matters most. If the SWG is happy and generating chlorine, then all is good. There are only two conditions where a SWG will give a false reading:

1) The cell is failing. This is usually indicated by the "Low Salt" warning occurring more often than normal.

2) The water is cold, as in the this case, AND the SWG is known not to compensate the readout for cold water. BTW, what brand/model do you have?

Other than these two conditions, I would rely upon the SWG readout.

Also, salt strips can give erroneous reading as well and tend to go bad quickly if not stored properly. Plus I find that they are not as accurate as a drop kit and tend to read on the high side.

 

[jamie1983]

It is a Hayward Turbocell T9. I believe it was reading 2200ppm, I know it's too cold to generate chlorine, but wasnt sure if I needed to add salt now or wait until it warms up.

 

[mas985]

The Hayward units have temperature compensation for the salt readout. Mine is fairly accurate down to 50 degrees. Below that the unit doesn't generate salt anyway.

One thing I forgot to ask is the cell age. Failing cells tend to read low salt.

But, if you have had a lot rain over the winter that required pumping out of the pool or overflowed into an overflow drain, that will lower the salt level and would be a reasonable explanation for the lower salt level. If this is the case, then it is probably safe to add salt.

 

[jamie1983]

The lower salt is most likely due to the rain we have had. The unit is only a year old. The water/temp is too low to generate salt, that was the reason I was asking if I should bother adding the salt now or wait a month or two for the water to warm up. My pool is hanging right around 42-45 degrees.

 

[mas985]

If the water is not warm enough to generate then there is no harm to wait until the water warms up. I agree that it was probably the rain. That will do it every time.

 

[Mark_Watermaid]

The reason for the low salt reading is the water temperature. At that water temperature the unit is probably calculating salt at about half of the actual reading. Almost all units shut down at water temperatures below 60 to 70 degrees. There are a couple that will generate at any water temperature. For those units you don't adjust the salt level you simply run the unit. The electro chemical reaction is a function of water temperature so production will be reduced but you will still be generating chlorine. The good news is that cold water slows algae growth so chlorine demand is reduced as well. If you add salt to increase production, you will be in trouble when the water warms up. The only way to reduce salt levels is to dump water and refill. Not a great thing to have to do. Salt test strips a okay for a rough calculation of salt in a pool. I have found them to be out as much as 1000 ppm at times. The best is a digital probe with temperature compensation. There are also some good drop kits that are accurate as well

Mark _Watermaid

 

[duraleigh]

Hi, Mark,

Welcome to the forum. :lol:

Dave

 

[mas985]

The reason for the low salt reading is the water temperature. At that water temperature the unit is probably calculating salt at about half of the actual reading.

The Hayward/Goldline units compensate salt readout for water temperature. Mine reads the same salt level from 50-105 deg F. Not all SWGs do this but the Goldline units do.

 

[Mark_Watermaid]

Thanks Dave.

Thanks Mark Good to know. I also believe that Hayward/Goldline units shut down at water temperatures below 60 degrees

Mark

 

[mas985]

Goldline units shut down at 50 degrees.