Manufacturer Recommends Low CH. Why?

[mooseau]

I was browsing chlorinators, seeing what is available in the event mine dies in the future. In Australia, our SWGs typically have high salt requirements, but I noticed one brand claimed CH must be between 100 - 250 to avoid premature death. All other recommended chemistry parameters are aligned with TFP, which is refreshing.

My math suggests that this is a very bad idea, negative CSI would be to low.

Why would they recommend such a level? I paste the quote below:

HARDNESS
100 to 250 ppm. Levels higher than the recommended level will result in a less efficient cell in regards to its chlorine production, a more frequent need for cleaning, and a chance the cell will fail prematurely. To minimise chances of high hardness levels minimise or avoid the use of chemicals containing calcium, especially, "Calcium Hardness" and calcium-based granular chlorine.

 

[Texas Splash]

Why would they recommend such a level?

Scale. It's their way of trying to keep owners from developing scale on the cell plates, but it does not address the potential of problems for a plaster pool. You still need to properly manage your CSI if you have a plaster pool. Managing the pH, CH, and TA (together) is the best way to address this issue, not just allowing the CH (alone) to become too low.

 

[mooseau]

Yeah, seems poor advice. The same manufacturer said it can even work with salt outside of maximum. Dunno if that is true or not, not sure I would test it.

I've operated my current SWG at the high salt end, and at 90% output, it melted the positive lead twice. Even though the manufacturer claims it will detect and prevent failure at high salt levels.