Aalkalinity question

I'm a new pool owner and am busy learning about pool chemistry and how to spend money. I think I have the basics, and that pH is important, along with TA and CH. I bought a salt system and had it installed; it seems to be working well.

My question has to do with why the alkalinity has been dropping. It went from 90 to 40 in about two weeks and the pH dropped with it (that part I understand). I bumped it back up to 70 and the pH went from 7.0 to 7.4. I'll probably add some more baking soda to get it up to 100 or so.

Anyway, the only thing I can think of is that there are a lot of pine trees around our pool (we're in Georgia) and several storms have deposited leaves, pine needles and tons of pollen in March. I tried to scoop them out, but at first I didn't realize that the water level was above the skimmer and there was lots of debris for a couple days.

Anyway, do leaves, pine needles, etc lower the Alkalinity (ie, more acidy)? Also, would (acid) rain also contribute to this as well?

Thanks

Unless you have concrete pool, low CH isn't important to you. High CH might be, especially if you are using cal hypo to chlorinate or have a heater.

I wouldn't worry too much about the alkalinity yet. Get your pool running, the pH adjusted, and an adequate stabilizer level, first. Once all that's done, you can look at alkalinity.

Ben

Thanks Ben. Actually, my CH was dropping as well and I raised it. I'm more concerned with the Alkalinity, mainly curious if leaves, pine needles, etc can lower the AK.

If both TA and CH were dropping, then it sounds like you might have a leak, assuming your fill water is lower in CH and TA than your pool and that you have auto-fill. Either that or you've got rain overflow diluting the water.

Leaves can have tannins that can be acidic which mostly lower pH and somewhat lower TA, but not by as much as you are seeing. I'll bet you are using test strips as those are notorious for inconsistent and incorrect results. Get yourself a good test kit, the Taylor K-2006.

I grew up in GA, and never saw large quantities of acid rain- but plenty of tannins! Oak, cypress, sycamore, etc...
Around Atlanta may have worse acid rain, but the more suburban and rural areas aren't significant!

Quote:

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Originally Posted by chem geek

If both TA and CH were dropping, then it sounds like you might have a leak, assuming your fill water is lower in CH and TA than your pool and that you have auto-fill. Either that or you've got rain overflow diluting the water.

Leaves can have tannins that can be acidic which mostly lower pH and somewhat lower TA, but not by as much as you are seeing. I'll bet you are using test strips as those are notorious for inconsistent and incorrect results. Get yourself a good test kit, the Taylor K-2006.

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No, I have a nice taylor kit I got from Leslie's that measures Cl, pH, TA, CH and CYA. Cost about $50 and does a nice job, so I don't think measurement is the problem. I think it was the storms that hit us in the Augusta area in late March and dumped lots of pine pollen and leaves in the pool. It seems to be stabilized now.