Swcg Questions

[E2Grunt]

I have a 30,000 SWCG system.

Is there a low temperature when salt systems are no longer effective and I have to add chlorine manually?

Someone told me below 50 degrees ambient temp that the salt system won't generate and I need to add tabs.

Also, the pool is about 8 years old and I had it retrofitted with the salt system about 3 years ago. Sense then I have had some major deterioratinon of the coping. It's a white natural stone not sure what kind. Some have said thats its the salt system and some say that I may need to run more extensive testing of the water beacuse other things can cause it.

What other chemistry issues could be causing this? What should I be looking for and what should I be testing for?

[chem geek]

The SWCG systems require a certain amount of conductivity of the water to be effective and such conductivity drops as the temperature drops, so yes they have a cutoff around 50F or so (it varies somewhat by manufacturer) so that they don't burn out their cell by trying to overcome the extra resistance (via higher voltage, if they vary voltage to keep output constant). You should just use 10% or 12.5% chlorinating liquid or Clorox 6% unscented bleach, not Trichlor tabs, unless your Cyanuric Acid (CYA) level is low and you want to increase it. With Trichlor, for every 10 ppm Free Chlorine (FC) that it adds, it also increases CYA by 6 ppm. Usually with the water so cold, the chlorine usage will be very low, especially if you cover the pool or it is not exposed to sunlight. So adding chlorine once a week is usually sufficient. In my own pool that has a mostly opaque pool cover and whose water temperature is now around 50F, my chlorine usage is 1 ppm FC in 2-3 weeks.

As for your coping, you should first calculate your saturation index using The Pool Calculator using accurate numbers from a good drop-based test kit such as the Taylor K-2006. If your saturation index is less than zero, then the water can dissolve calcium carbonate from plaster/grout and some types of stone. More likely, however, is that the higher salt level in the pool is causing deterioration from the splash-out and evaporation cycles that cause salt recrystallization pressure in small cracks in the stone that causes it to break apart. This blog talks more about that kind of problem. It doesn't happen as quickly in all areas, possibly due to regular rains in the summer in some regions that wash away the salt. You can consider sealing your stone to prevent the deterioration or to rinse it off regularly if the damage is mostly on the splash-out surface. Some kinds of natural stone can degrade quickly even without the extra salt in the water. Some types of limestone are particularly soft, though it depends on where it is mined.

[E2Grunt]

Thanks Chem Geek, thats exactly what I was looking for.

Also, there are three wires coming out of my goldline aqua rite salt system. I know ones goes to the cell, and one goes to a flow switch. But what is the third sensor? I couldn't find anything on goldlines website.

[Pool Clown]

E2,

It could be the com wire for an automation system. Where does this wire run to?

[E2Grunt]

Where does this wire run to?

This part is actually for a nieghbor. But the problem is it runs nowhere. The previous owner cut the wires to the cell, the flow switch and this third "sensor". The sensor was laying on the ground, its round (about 3/4" to 1"), black, with a nipple that points out. Looks like others I have seen pics of that appear to be drilled into a pipe and held on with a hose clamp?

We were tryong to figure it out so we could see what parts of his salt system do and dont work. THen maybe have it running for him in the next month or so.

[Pool Clown]

Part you describe sounds like a temp sensor. But i am not aware of a separate sensor for the Gold line unit you describe. Do you show where (pic?) this wire connects to inside the control box?