Ta is being stubborn

[mj2]

My TA is at 40, been trying to get it up. I lowered ph with acid twice, then added Baking soda, the first time it came up none, but we had a bunch of rain, the second time it only came up 20. I've been using the pool calculator. I've waited 24 hours between measurements and it should have come up to 80 the second time. What else could be affecting this?

 

[JasonLion]

When raising TA, you add baking soda and do not use acid. Adding acid lowers TA.

 

[Richard320]

My TA is at 40, been trying to get it up. I lowered ph with acid twice, then added Baking soda, the first time it came up none, but we had a bunch of rain, the second time it only came up 20. I've been using the pool calculator. I've waited 24 hours between measurements and it should have come up to 80 the second time. What else could be affecting this?

How are you chlorinating?

Dichlor and trichlor - pucks and "shock" are very acidic and will mess with pH. So will adding acid.

There's also the possibility that your tests are wrong. How are you testing? If it's a drop test, sometimes static electricity messes with the drop sizes. Wiping the tip with a wet towel will get rid of it. If you're using a test strip, that's your most likely problem.

 

[mj2]

Okay, but adding baking soda raises PH, so I was lowering it before adding baking soda to try to get TA up without raising PH of f the chart. That makes sense to me from what I've read, but perhaps I'm missing something. It did indeed raise PH, I went from 7.0 to 7.8 but I didn't meet my TA goal.

 

[mj2]

I did a drain and fill recently and have only chlorinated with calcium hypo and bleach. My CYA should be at 30 but I don't have a reliable test, only a test strip that I will throw away soon. I'm testing with a cheap kit from ace hardware, have a tf100 on the way based on y'alls recommendations. Water looks great but i am wanting that TA buffer to get my ph stable.

 

[duraleigh]

Okay, but adding baking soda raises PH,

Not really. Off to Pool School for you!!

 

[mj2]

You gotta be kidding me. Pool School is where I learned that. "You can raise TA with baking soda. It is often best to make large TA adjustments in a couple of steps, testing the water after each one, as adding baking soda will also affect the PH and you don't want the PH going out of range"

 

[Butterfly]

Baking soda has only a little effect on the pH. To see just how much, go to the Effects of Adding Chemicals section of the Pool Calculator, near the bottom.

 

[mj2]

I see that the effect appears to be very slight from looking at that, thank you for pointing that out. Doesn't match my reality though. I added only the acid to lower PH, then I added only the Baking soda to attempt to raise TA, with at least 12 hours of circulation after measuring from either. Empirically it seems I shouldn't have bothered with the acid first. But I added nothing else during that time. Doesn't make sense to me at this point.

 

[Butterfly]

If you give us all the #'s we'll go over the calcs with you if you want.

Acid will lower both TA and pH.

 

[mj2]

OK. I'm going to wait until my tf100 test kit shows up and then post my numbers and talk with you guys about them. I have a pretty good understanding of scientific method, seems clear to me that you have to only adjust one variable at a time to be able to predict results, but the pool seems to be acting otherwise now.

 

[mj2]

I guess we need to call this test kit fail (edit, my OLD one). After a few days of very little attention and like 12 inches of rain (not kidding) here are the results from my new TF-100.

FC 2
CC .5
TC 2.5
PH 7.5
TA 90
CYA < 20

 

[duraleigh]

I am a bit late to this thread but let me say first off to ignore your TA....not only does it appear to be fine but it should be one of the last items to adjust.

1. Why is it "fail"? I don't understand.

2. What does your water look like?

2a read "The ABC's of Pool Water Chemistry" up in Pool School

3. You need to bring your CYA up to around 40-50 ppm. Do you understand it's purpose?

4. After the CYA addition, bring your FC up to around 4 ppm and then make sure it stays there by replenishing.

Perform those dosages and tell us about your water.

 

[mj2]

Sorry, I wasn't very clear. What I meant is that my old test kit was likely giving me inaccurate results, as the results from my new TF-100 seem to make sense given what I added to the water. I have much more confidence in my testing now. I already got chlorine pushed up to 4 and picked up some more CYA, going to test that one more time first because I didn't do the test outside, etc. (Yes, I understand the CYA is to keep the sunlight from eating my chlorine)

Thanks to all that have responded!

 

[harleysilo]

So you've seen and understand this pool-school/chlorine_cya_chart_shock

 

[mj2]

Yes, I think I understand the chart. At .5 CC I figure I'm on the border of needing to shock or not, but at under 20 CYA having 4 ppm chlorine seems fine. The pool is crystal clear and I'm going to reevaluate after pulling a full set of test results tomorrow, including doing the CYA test just like the testkits video I watched, as I really think my first test result with the TF-100 doesn't jive with the 4 lbs of CYA I recently added to my 16K gallon pool. I do intend to move the CYA up higher after I'm more sure of the current level.

 

[Smykowski]

.5 CC can be treated the same as zero. If it goes up to 1.0, that's a problem.

Remember that it can take a week for dry CYA to show up on the test.

 

[linen]

Just out of curiosity, what test kit were you using?

 

[mj2]

I was using this 4-way one from Ace hardware and relying on the pool store for other tests.

http://www.acehardware.com/product/inde ... Id=1381660

 

[linen]

That test should have been decent for what it measured...but trust the TF-100.