Brand New Build, HELP!!

[PoolDoc]

Thanks Janet for the "bump". I've been leaning toward SWCG for sanitizing, but the local pool shop said it would be corrosive on my automatic cover and pool deck/railings/copings. Any truth to this?

Yes!

1. The salt itself has issues of attacking the cement in the plaster and deck materials. Buyers should be aware that if you have salt water above 2800 ppm, (often 4000 to 5000 ppm), you will need to reseal your coping every year, especially if it is a porous stone like limestone or travertine. Otherwise, the salt will dry and start to etch the coping. Besides sealing the stone, it is also advisable and an added precaution to hose down the coping at the end of any swim day with fresh water. Although the salt water in the pool may not be corrosive at levels of 3000-3500 ppm, when that water hits the coping and evaporates, it leaves pure salt behind. The pure salt is corrosive and is the main cause of the corroding coping. Most autocover manufacturers now void their track warranty if a salt system is used.

Deck corrosion seems to be more of an issue in areas with infrequent summer rain, and natural stone decks. Arizona -- which your IP address indicates is your likely location -- is DEFINITELY an area where you could have a problem with deck corrosion. But I think the warranty issue with the cover mechanism is your bottom line.

I also found this information:
1. A common misconception is that saltwater is more corrosive than chlorine, but 4ppm of chlorine is 10 times more corrosive than 4,000 ppm of salt.

I don't think this is true. Do you have a reference or link?

[CarlD]

Hi Russ!

Corrosion resistance is a function of the grade of stainless steel used. SS comes in all sorts of "flavors" and is not all the same. Some types (like kitchen and hunting knives) will corrode if left submerged, but if dried after use stay clean for years...but they are an SS designed to hold an edge. Other grades are designed for constant immersion, like the inside of tanks. It's all a matter of getting fittings rated for salt water use--or making them easily replaceable (Plan "B").

The great thing about a saltwater chlorination system and the B-B-B Method is that they are TOTALLY compatible with each other. Many (in fact, I'd say all) of our members who have SWCGs incorporate their SWCG into their B-B-B pool maintenance program--they just don't have to add chlorine as often and have to watch their salt levels.

About the only differences between a B-B-B + SWCG and B-B-B alone is that ideal levels of Free Chlorine (FC) versus stabilizer (CYA) is much lower (SWCGs use fairly high CYA levels), and that Total Alkalinity (T/A) is generally at the low end or even below the general minimum suggested level. Neither is a big deal. So, if your CYA is 80ppm, with an SWCG you want your FC to be at least 4ppm (5% or more), but without the SWCG, it should be between 5 and 10ppm.

As for mineral systems, well, we flatly, strongly recommend against them. They are fundamentally copper/silver erosion systems that cost more per year than you can save on chlorine. (do the math: If the mineral cartridge costs $100 per season and is supposed to cut chlorine usage in half, it has to save you at least $100 in chlorine....that's 30 gallons of 12.5% liquid chlorine, equal to 60 gallons of Bleach...since that's only half, it means you have to be using at least 120 gallons of bleach a season and save half of that just to break even on the seasonal cost of the cartridge.)

Carl