Greetings:
I am the owner of a brand new Pebbletek pool with SWG, and am now at the 2 month point since the pool was filled in mid October. The SWG was started up December 1 (almost 3 weeks ago). It is an outdoor pool, but equipped with an motorized cover that is close nearly all the time (total open time for swimming and maintenance less than 30min/day).
I have been monitoring pH and FC daily and running the full suite of tests at least once a week. The full list of numbers from the last full test:
pH 7.5
FC 6.5
CC < 0.5
CYA 30
CH 400
TA 100
Temp 73 -- note we heat it for weekends when sunny weather is expected so the temperature varies from mid 60s to 85 when in use.
Pool is 6100 US Gal.
The pattern for the past 2-3 week now has been that I watch the pH rise, and when it gets to 8.0 (and CSI > 3.0) I add ~16 oz 31% HCl. And when I test again the following morning the Ph is back down to 7.3-7.4 (CSI ~ -0.3) it then takes 3-4 days for the Ph to rise back to 8.0.
I think I have read all of the "Further Reading" posts on the subject here as well as watched Marty and Matt's video on the subject. (Which brought back vague memories of Collage Chemistry class).
So I gather from the reading that reducing the TA will lower the rate of Ph rise, but I have some questions about the published process. You advise using acid to lower the Ph to 7.0-7.2 (which lowers TA) then aerate to raise the PH again. Is there a threshold in the chemistry at Ph of 7.2? Or is that just a suggestion to make it go faster?
I also read this post by James W: pH rise in new plaster? And based on that it seems like the better strategy would be to add acid only as needed to get the CSI down to ~0 (which for my current conditions is about Ph 7.5) as lowering further than that is probably just adding more Calcium Carbonate from my new plaster and defeating the intent.
But then I don't know the relative speed of these reactions, how long should the Ph be at 7.0-7.2 in order to significantly lower TA before you start aerating to bring it back up. And how does that time compare with how rapidly the Calcium Carbonate surface layer on the plaster will dissolve with a CSI of -0.5 (which according to Pool Math is where my water would be if I drop the pH to 7.0).
I am the owner of a brand new Pebbletek pool with SWG, and am now at the 2 month point since the pool was filled in mid October. The SWG was started up December 1 (almost 3 weeks ago). It is an outdoor pool, but equipped with an motorized cover that is close nearly all the time (total open time for swimming and maintenance less than 30min/day).
I have been monitoring pH and FC daily and running the full suite of tests at least once a week. The full list of numbers from the last full test:
pH 7.5
FC 6.5
CC < 0.5
CYA 30
CH 400
TA 100
Temp 73 -- note we heat it for weekends when sunny weather is expected so the temperature varies from mid 60s to 85 when in use.
Pool is 6100 US Gal.
The pattern for the past 2-3 week now has been that I watch the pH rise, and when it gets to 8.0 (and CSI > 3.0) I add ~16 oz 31% HCl. And when I test again the following morning the Ph is back down to 7.3-7.4 (CSI ~ -0.3) it then takes 3-4 days for the Ph to rise back to 8.0.
I think I have read all of the "Further Reading" posts on the subject here as well as watched Marty and Matt's video on the subject. (Which brought back vague memories of Collage Chemistry class).
So I gather from the reading that reducing the TA will lower the rate of Ph rise, but I have some questions about the published process. You advise using acid to lower the Ph to 7.0-7.2 (which lowers TA) then aerate to raise the PH again. Is there a threshold in the chemistry at Ph of 7.2? Or is that just a suggestion to make it go faster?
I also read this post by James W: pH rise in new plaster? And based on that it seems like the better strategy would be to add acid only as needed to get the CSI down to ~0 (which for my current conditions is about Ph 7.5) as lowering further than that is probably just adding more Calcium Carbonate from my new plaster and defeating the intent.
But then I don't know the relative speed of these reactions, how long should the Ph be at 7.0-7.2 in order to significantly lower TA before you start aerating to bring it back up. And how does that time compare with how rapidly the Calcium Carbonate surface layer on the plaster will dissolve with a CSI of -0.5 (which according to Pool Math is where my water would be if I drop the pH to 7.0).
