I discovered something over the weekend that reminded me of discussion we used to have concerning chemical companies claims that CYA doesn't matter.chem geek said:
Me, too.tedinelkgrove said:I can only imagine what they teach in the "certification" courses. Strange how he didn't know there is a relationship between CYA and chlorine levels.
You ain't gonna stay below 50 ppm for long on a steady diet of pucks!If the pool is using stabilized chlorine or contains cyanuric acid check the cyanuric acid level. If the cyanuric acid level is greater than 50 ppm the pool should be drained and filled with fresh water until the cyanuric acid level is below 50 ppm.
Now that's an interesting point, running a higher FC level means wearing out the cell and a higher chlorine loss, why?chem geek said:Also, maintaining a higher FC in an SWG pool means more chlorine loss so a longer SWG on-time. That often leads to a faster rise in pH so more acid needed to compensate for pH. The extra cost isn't just in the SWG on-time electricity and shortened cell life, but also in the acid and inconvenience in the possibly greater frequency of pH adjustment.
JasonLion said:Every pool is different, so our recommendations are not perfect for everyone, but it was our intention to recommend levels that work for just about everyone and are trouble free. I wouldn't call them "borderline" in any sense.
I wouldn't either. I wasn't referring to TFP's recs. TFP's recs for my MinFC and TargetFC are 4/6ppm, and I'm planning to target 6ppm this year. Very happy with that, and I have confidence that it will work well based on the great advice and explanation I've gotten here over the past several months. I was referring to the lower levels that are predominant in the industry and outside of TFP -- 1-3ppm. Just very generally speaking, 1-2ppm seems alot riskier than 4-6ppm. I'd just rather run a bit higher and dramatically reduce the risk of getting algae.
The cell in a SWG will produce a fixed amount of chlorine in it's lifetime. If you run at a higher FC level it will shorten the cell life in a very predictable way. Replacing the cell in a SWG can be fairly expensive, and in the long run ends up costing just about the same as it would have cost to add chlorine manually. So there is nothing "hard-to-quantify" about it.
I respectfully disagree. Maybe "hard to quantify" isn't exactly the right term, but the point is that most people running SWGs aren't going to notice the difference in a cell that lasts for 3 yrs vs one that last 3.5 yrs. That's just way too abstract for the average homeowner to think, aha, the cell life was shortened by 6 months because I ran at 6ppm instead of 4ppm. I'm talking very generally here, not just about the careful, more conscientious TFP followers. I know what you are saying and I totally agree that there's no need to run the FC significantly higher than necessary. My original question was more of a hypothetic one, and you guys have helped me to understand the issue better. I'm still relatively new to pool ownership, and I personally prefer a small cushion (thus I'm using TargetFC instead of MinFC).
If you want to spend the money to get some peace of mind, then fine. But most people are interested in reducing costs, so much so that it is one of the fundamental goals of our system of pool care.