Why so much acid?

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gregsfc

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May 27, 2014
202
Cookeville,TN
I'm doing the TFP method. Easy to add a little bleach every day. Works great! A wonderful sense of satisfaction and pride when you get the dosing just right, and your tester confirms that you're staying between min FC and the target, and you know your pool is staying clean. But I'm constantly running PH around 8 or a little more unless I add almost as much acid as I do bleach. I read somewhere on the site that the PH spike is only temporary when adding bleach, but even if my FC gets down below 1 before adding my daily dose, my pool still has high PH. I'm finding, if I add 8 oz of acid each day, I can keep it in range. The high PH is confirmed at the pool store, so it's not just my tester. I'm not aerating. I've not even been in the pool this season. Last year I was running high FC, because my CYA was over 70. I thought that was the reason I was constantly fighting high PH, but this year, I opened to 31 and am staying between 2 and 4 FC. Have shocked a couple of times right after opening, even though it probably wasn't necessary. So is constant adding of acid normal? Something to do with shocking with bleach? Because it's a small pool? Or something else?

I've got an 18' round with vinyl liner with a strong pump and large filter for this size pool, but the pump is not so strong that it creates a whirlpool.
 
Richard320 said:
Do you have really hard water? If TA is really high, it will drive the pH up quickly. Your area isn't noted for Limestone caves or anything, is it?

:testresults:
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Store personnel have told me that water is unusually soft by nature in my area. Natural calcium levels shown from pool store sample sort of confirm that. Some caves and some limestone block plants in my area, but I don't think any are near water sources.
 
The simple fact is that when it comes to pH control in pools, each pool is different and there are many factors that effect the pH and pH trends, these include, but are not limited to, fill water characteristics, alkalinity of wind blown dust, pool finish, and types of pool chemicals that are used, some of these things are under our control, and unfortunately some are not, the best we can do is manage what we can.
 
So far this season, both my tester, and the store sampled tests have shown low TA; around 60. I only recently made my first adjustment to Alkalinity and raised to about 110 (according to my tester but have not brought in another sample to the store). I tested alkalinity using the one-drop-at-a-time acid drop method after putting in a couple of doses of soda 1/2 at a time, but at the same time, I started adding muriatic acid every day or two and have all three in check according to my test kit.

I need to get the recommended test kit. I've got a drop system from the pool store. Sort of panic this Spring realizing I needed to get a kit and bought the one at the store. Don't know the brand, but will get the recommended tester linked on this site.

It seems like as soon as I start adding daily bleach dose, the FC does exactly what I expect, but the PH wants to stay up around 8 or a little more and then gets no higher. But if I continually add acid, I can keep it in check. If I get PH in range; then add my 20 ounces or so to bring FC up to about 4; test it the next day; the FC will be around 2 (which is what I want to do); but PH will be right back up to 7.8+ even with the FC back down to the minimum. However, so far this season I'm finding that if I go ahead and add about 8 ounces of muriatic acid 31% either before or after I add the bleach, then when I test the next evening, everything is good.

This isn't that hard to manage, it's just that I'm not sure if I should just let the PH gravitate and stay high; or just keep buying and using muriatic acid; or try something else. I've not read about this anywhere from anyone else, so I was just wondering what might be going on. The bleach is Dollar General 8.25%. I put it in the calculator as 7.86%, since the label shows that as the yield. It seems to be accurate on strength the way I'm dosing it; maybe just a little strong since the calculator tells me to add 24 ounces and I'm finding about 20-22 is about right. But it's still early season, so it'll probably go up a little with more sun and higher temp pool.

Worked on my signature. Hope it comes through on this post.
 
We recommend TA around 60 to 70 for exactly this reason. Raising TA to 110 is driving the PH up, and will continue to do so as long as you maintain the TA that high. TA should only be that high if you are using an acidic source of chlorine, like trichlor tablets.
 

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JasonLion said:
We recommend TA around 60 to 70 for exactly this reason. Raising TA to 110 is driving the PH up, and will continue to do so as long as you maintain the TA that high. TA should only be that high if you are using an acidic source of chlorine, like trichlor tablets.
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Okay. I guess I haven't read everything on here or have forgotten some things, but I didn't realize TFP recommended lower alkalinity levels than the store test report. But according to the above recommendation, I've just done something that will ensure that I keep adding acid. The first response to my inquiry was that I needed to get my alkalinity in range in order to control my PH. After reading that reply, I raised my alkalinity to what I thought was the correct range, but I guess I should have found the recommended range on here and not by the pool store test report.

Keep in mind though what I stated in the beginning. I only just recently adjusted my alkalinity from 60 to 110 (which, until just now, I though I had put alkalinity exactly where I needed it). So understand, from the time I opened the pool until just two days ago, my alkalinity was at 60, and my pool was gravitating at 8.0. I left it alone for a while, but about a week ago, I got some muriatic acid and began controlling my PH. So unless someone on here thinks that 60 is too high, my drifting PH was not being caused by high alkalinity.
 
You didn't make the increase/adjustment based on our recommendations, and mixing our advice with the Pool store will cause these errors and confusion. You really need a proper kit and solid numbers for us to truly help you. There are other factors that contribute to pH rise, but TA is a primary one. I would suggest getting a proper kit, and some good numbers based off those tests and make your adjustments according to those.
 
pooldv said:
Here are the TFPC Recommended Levels.
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Thanks for the link. I'll put this as one of my short cuts and quick references to put with my pool kit.

I think you guys have helped my beat this one to death. This is not something I feel like I must solve; just something I wanted to learn and hoped there was an easy explanation. I'll definitely get the recommended test kit and use the recommended levels before any other inquiries.

Thanks for the input. Folks are asking for test reports, but I'm not sure what else you need. My store report from two weeks ago showed slightly high PH--I think 8.1, Alk 60, FC 3.4, CC 0, CYA 31, Hardness 160. This was the pool opening levels other than the bleach I had added. No dissolved metals or anything else that I can remember that would show a problem. I didn't keep that report. Prior to taking a sample to the store, I opened with some FC showing on an old test strip that may or may not have been accurate. I shocked it up to about 15. Let the FC drop down to about 4 (according to my test strip), and then took a sample to the store with the approximate results above. Bought a drop sample kit while I was there. Since the time of the store report my alkalinity has been showing 50-60 on my two personal tests (until I recently adjusted it); my PH was showing 8 or higher each evening after the FC was back down towards the minimum level (until I started adding acid); since adding small amounts of acid each day, I've now got the PH worked down middle of range at the same time that the FC is near minimum sanitizing level for 31 CYA, but if I add liquid bleach one day, without adding acid, it'll be back up towards 8 the next day. I've not shown any CCs yet. Pool is crystal clear and has been since going to the TFP method, even when I took the cover off.

So I guess my point is that everything is great. No complaints really other than I didn't read anything in the TFP literature about the need to constantly lower PH when applying this methodology and was hoping to understand what was going on. I don't think I've ever added PH up. Pool has never needed it. I have over done it on the acid a couple of times last year down to about 7.2-7.3 from around 8, and by my measurements it dropped the alkalinity out of the pool down to about 40 each time I made that mistake. I added soda to fix it, and in no time at all, the PH would be back up around 8. So far this year, I've been adding just a little acid at a time; no more than 16 fluid oz at a time. Everything looks at measures out great!
 
If you don't have a recommended test kit, such as the TF-100 or K-2006C for your pool and your listening to pool store advice then you're not following TFP method.

Blending of the TFP advice and pool store advice is not going to end well. Your pH rise is a recurring problem because of the increase in TA that you made, which would not have been TFP advice.
 
Could aeration be a possible cause? Since you have an AGP it's less likely you have water features like a waterfall but do you have any sprays jets or returns that are causing a lot of surface turbulence or do you have any air bubbles coming out of the returns? What speed do you run your pump on, fast or slow?
 
JVTrain said:
If you don't have a recommended test kit, such as the TF-100 or K-2006C for your pool and your listening to pool store advice then you're not following TFP method.

Blending of the TFP advice and pool store advice is not going to end well. Your pH rise is a recurring problem because of the increase in TA that you made, which would not have been TFP advice.
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The store sample report should be right, or close to right, as far as I know. Nothing far different than what any test kit I've ever used has shown. I don't take their advice but I like all the numbers it gives in a print-out form, and I think I'll keep using them to confirm things even when I get the recommended kit. As for their advice, they don't really give me much. They know I know what to do. The report has advice on it, and most of it is all wrong. I just missed the part about recommended levels being different except for FC based on CYA. I didn't know the stores were wrong about these other recommended levels. Don't know how things will end, but the pool has been great for almost a year now, even without one of those recommended test kits.

Once again, when I first posted, my test kit showed TA between 50-60; the store report showed 60. I had not done anything to my pool, including adding soda, when I first inquired about this phenomenon except shocking and maintaining FC. If my two testers and the store tester all underestimated the TA level and only the recommended test kit will give me the correct TA, then I guess it's possible that it was too high and has been too high for a year straight. This phenomenon has been happening ever since I started adding the necessary bleach daily to stay in the target range no matter what my TA may have been. It does not happen with the other types of chlorine.

The PH has not caused any problems whatsoever with swimmers, sun bathers, or pool equipment so far. All the other numbers have been easily adjusted and easily controlled with expected results thanks to the information on this site. This was more of a question about me trying to understand the "why" and not really a call for help; though it could save me some money and some time if this weren't going on.

I know I need the test kit, so when I get the 50 bucks and go back and find the link, I'll get it.

- - - Updated - - -

gtemkin said:
Could aeration be a possible cause? Since you have an AGP it's less likely you have water features like a waterfall but do you have any sprays jets or returns that are causing a lot of surface turbulence or do you have any air bubbles coming out of the returns? What speed do you run your pump on, fast or slow?
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Yes; thanks. I've had this thought too but felt that I'm not experienced enough to make such a determination.

I've said I'm not aerating, but I wonder when I'm running the pump on high a couple of hours per day and that jet is sending a few bubbles around the pool at the surface (about a 1/4 way around); if I'm not getting some unintended aeration. The pool is 18' round and so it circulates the water pretty quickly but not enough to create a whirlpool.

I'll go back and read everything. It's been nearly a year.

I'll get the test kit; and try it again and see what happens.

Thanks everyone for the help and insight.
 
Greg, we don't distrust store results for no reason. Some of us have been burned trying to guide people through situations with store testing until their own kit arrives. Finding that when it does, levels they've been given were wildly off. Many, many more times it's been shown over the years that they shouldn't be trusted. Perhaps you have good results, but the truth is you never know until you run the numbers yourself. Even here, your numbers seem a little contradictory, meaning low TA, and High pH which aren't two things that normally go together. Once you get the kit and run the tests, you'll know for sure. Until then, it's a question.
 
OP again. Still using up my current test kit before purchasing a new one recommended on here. I can't see changing anything right now when my only problem or concern is the minor issue of having to add a little acid three or four days per week to stay in recommended range, and I can't see buying a new kit when I'm still consuming the one I've got and I've got a crystal-clear pool. And lastly, FC and PH seem to be testing out in a very predictable way and see no need to throw this kit out when everything is going so well. I will heed the advice on here, however, and get a recommended kit to get my CC's, Alk, CYA in the future instead of the pool store reports. I can use my current kit for Alkalinity using the acid-drop test, as it seems to be predictable as well. Not sure how I'll know when it's time to shock; maybe just do it the pool store way for a while based on a lapse of time; maybe every couple of weeks, or I could go by my OTO chlorine reading after 2 minute reading of FC as the test instruction state.

I now know where I got the alkalinity range that I thought was appropriate (80-120), and it wasn't just from the pool store. It came from the TFP calculator provided. It's right there on the guide that comes with the calculator, so the recommended level chart sort of contradicts the recommended level shown right on the calculator.

Pool still looks great, still doing a daily regimen of bleach to stay in target range using an OTO tester and the calculator on here. I've found that for right now, probably due to a lower current consumption rate due to the spring season and/or not much dirtying of the pool, alot of cloudy days or whatever the reason, I have to reduce the chlorine dose shown in the calculator by about 20% or I start moving FC up and out of the target range over a period of a few days. But if I take the result and subtract about 20%, it's very predictable using my cheap OTO test that's in my kit. But I don't see this as a problem to be using less chlorine than what the calculator shows, and really, after finding this website and following my old method of using the pool store every couple of weeks to get CYA and CCs and Alk, I have had no issues whatsoever, except for the constant acid adding, but that seems to be a problem only because I choose to fight my pool's natural tendency to gravitate towards 8.0

Last summer at times when I'd run out of acid or just from growing weary of dawning protective gear and adding acid, I'd just let the PH go; let it drift up to where it wants to be; around 8.0; and still had no problems with the pool. My biggest worry in that situation was that I had read on TFP somewhere that the FC would not be as effective at a higher PH and thought that maybe that could lead to not enough sanitizing power, which could lead to a cloudy or green pool over time, but nothing like that's ever happened to my pool; not ever since going to the BBB method, even though I've never added that last B or any other PH increaser ever since I quit using the pucks. Really, the only problem I had last year was the couple of times where I accidentally over dosed acid and my test showed that I dropped my alkalinity out, and then I'd add soda, but the high PH would come right back; just a day or two, even if it got down to 7.1 or so. I've done this acid over dose mistake once this year. So really, the only issues I've had since going BBB style of pool care is adding too much acid.

So I went moonlighting on you guys to see if I could find something about my situation and viola, there it was...an article about the benefits of running a pool at high PH. Not really following this advice right now; mostly because the article doesn't go into detail about "why it's okay to do this"; and so I'm just being a little more careful about diluting my acid real well and moving PH more slowly with acid, which means whenever it reads 7.8, I hit with a few ounces of acid, instead of waiting for it to hit 8.0 and trying to move it all the way back down at once, and I don't try to move it more than a couple basis points at a time because the times I've had trouble was when I got the PH down towards the lower range or tried to move it too far, too fast. All other times, it's been very predictable and controls the level as expected; at least as is shown with my tester.

I'm sort of forming the opinion offered up by Isaac-1, about PH levels on individual pools being affected by many factors that are individual to that pool, that location, and that water supply and cannot necessarily be solved on here with strict protocols. And so I don't think I'm going to let it bother me that much. It's just that I was hoping for a simple answer. And it doesn't look as if there is one.

http://www.poolsolutions.com/gd/hiphpool.html
 
There are typically two reasons why PH rises, aeration and high TA. Aeration is fairly easy to diagnose and solve. High TA can be too depending on the TA of your fill water.

You can lower TA to 60-80 to see if that helps stabilize PH at a lower level using this protocol, Pool School - Lower Total Alkalinity

Also, adding borates to the pool can help stabilize PH, here is more info on Borates - Why and How
 

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