Thanks
This thread already got split off another one to give xDom his own one
This seems to happen a lot with my posts!That would be a split from a split
What would be the problem if the CSI was acceptable but the CH was greater than 500?
I can't answer that for a FG pool. I can't really answer that for a plaster pool either. Some here let (or are forced to let) their CH get higher than that, 700 or more. And compensate that by maintaining pH out of range to satisfy CSI. I can't speak to the long term effects of that practice. I assume it is too difficult or expensive to exchange water to lower CH, so they do what they do.
Good info. I didn't know about eye pH until I learned it here. So my perception of the "ideal pH" for my eyes could very well be some sort of placebo effect. But the skin and eye irritation occurred before I found TFP. That was real. I had assumed it was chlorine related. Someone here explained it was more likely to be the acid overdosing, that my pool guy was doing, than the chlorine overdosing. Might have been the same thread that discussed the eye pH. The 7.5 number is what had stuck in my head.
So do you regularly test for TA? I read in another of your posts somewhere you don't add any TA increaser? What is your fill water TA?It would still increase from there. Evaporation leaves TA behind, and then you add more with fresh fill water. But with TA 30 fill water, that should be a slow process.
And each acid addition will bring TA down. There's a simple rule of thumb for those thinking metric: Take your pool volume in hecto litre, replace the hecto with a milli, and that's the acid amount that will reduce your pool by pretty much 5ppm. Example: You have a 30000 litre pool, that's 300 hecto litres. An acid addition of 300 milli litres (full strength MA) will reduce your TA by about 5ppm.
I wouldn't go below 50. You want some buffering left for things going wrong. Acid container slipped, acid added instead of bleach, it has all happened before. Pool service who takes over while on holidays throws in a few pucks. Whatever.
One issue with pH 8 is that you don't know if pH is actually higher, unless you have a well calibrated electronic meter.
Australian standard AS 3634 for private pools wants pH to be not higher than 7.8. This doesn't make much sense as a standalone rule, for the risks with higher pH they are mentioning things like reduced chlorine effectiveness (which is only valid without CYA) or scaling (it's not pH alone, CSI counts). In the end it's up to you what to make of that, and that you understand what you are doing and potential consequences.
Another thing is that around pH 8, and quite pronounced above 8, FC loss to UV starts to become more significant, particularly at higher FC/CYA ratios:
Chlorine and pH relationships. Chem experts knowledge?
OK, so I am a newbie. But, I’m ignorant of pH within Chlorine relationships. I can find very much data here on Chlorine/CYA, but what about pH? Basically without getting too technical……haha, (I’ve read Chem Geeks articles) I am trying to figure out the effectiveness of Chlorine at different pH...www.troublefreepool.com
I usually let pH ride through winter up to 8. In summer, I usually keep it below 7.8, I need those acid additions then anyway to stop my TA from rising. TA usually between 70 and 90.
So when you say that you add acid less frequently in winter, is this because the pH rises slower in winter or is it because you don't mind the pH being slightly higher in winter?
During the middle of the night, every night:
No, it's virtually unpluged. It wouldn't run if I wanted it to, below about 52°F. I dose the pool manually with liquid chlorine, once a week, for about 12 weeks a year (so ~12 times, which is not too bad, chore-wise).