rising ph levels

[jereece]

Thanks for your very interesing post. I want to learn more about this, because not too long ago I made a similar post about pH increasing and was told to increase my TA from 80 to 100 - 125. Here is a link to that post: http://www.poolforum.com/pf2/showthread.php?t=3715.

I do not have any water features that would increase aeration and I normally try to keep my return flow so that it does not splash. I have read on this forum that splashing can decrease TA, so I have always tried to keep return flow from splashing very much.

I believe I do see TA slowly decreasing. I have not taken notes on this, but my recollection is that it slowly decreases over time. I accounted this to the process you describe being accelerated when I add acid. Normally when my pH gets to 7.8 I will add acid to get it back down to 7.4 or so. But even when my TA was 80 (earlier this year), I still saw pH rising at about the same rate. After increasing the TA, I have not noticed pH rising slower.

So, are you saying that my TA will continue to decrease until it gets to a stable concentration and then pretty much stay there. And at that point, my pH should only rise about 0.1 units per week? If that's true, that would be great. I will pay more attention to my TA and see if I can notice where it gets to a stable point and if my pH increase slows.

Very interesting info, but it seems to go against what I have read so far which is to keep my TA around 125.

Thanks again for the interesting info.

Jim