Can't get TA down

[E Murph]

I'm about 10 days into the system. Pool looks great. I just sold all my old Tabs on Craig's list so I'm 100% in now
here is my latest test results
FC 5.5
CC 0
TA 140
PH 7.6
CH 250
CYA 45

I have added a gallon and a half of Muriatic acid over the last few days and I can't seem to get the TA down? I am running a fountain to aerate the pool. I've put enough acid in to get the ph down to 7.0 each time and it seems to come back up fine by the next day but the TA doesn't go down much at all. The water is balanced so maybe I should not worry about the TA? It does seem to keep driving my ph up though. If I leave the TA where it is will my PH keep creeping up?
Thanks for the help!

 

[cowboycasey]

Your numbers look good

You can take TA down faster by dropping it to 7/7.2 and drop it again at 7.4, after 7.4 it will raise slower and take you longer.. It will still go down but it just takes longer

 

[pooldv]

It is also fine to leave your TA as is. Lower your PH when it gets to 7.9/8.0. TA will slowly drop over time. The only real downside to high TA is if your PH rises quickly. And yours isn't really that high, we've seen worse!

 

[Richard320]

Hmmmm.... let's see now...

If pH is at 7.6 and TA at 140 and you target 7.2 pH, poolmath says 40 oz acid for your 15000 gallon pool. Down near the bottom, Effects of Adding Chemicals says 40 oz of acid will reduce TA by 10. Ignore the pH guess - read the disclaimer just below it. You're making a big change so the pH guess is way off. 10 TA is one drop on the test. That's within the margin of error. It's also easy to stop the test a drop too soon. Maybe the TA is really 144. The first test you read 140. The next test might be 136 and you see it also as 140. No biggie. The next round should make a big enough change to see some results.

Other sources of error could be that your pool is bigger than you think so that you aren't adding enough acid or the R-009 bottle has developed static electricity on the tip which makes the drops cling and end up smaller, so it takes more drops and gives a falsely high reading. Wipe the tip with a damp paper towel the next time you test.

More specifics Extended Test Kit Directions

 

[E Murph]

Good stuff! Thanks. I will update my signature. I'm convinced my pool is 16,000 gallons based on everything I've been doing. I changed it to 16,000 gallons in pool math and everything makes a little more sense. I love the part at the bottom of pool math that shows the effects of adding different things. Whoever designed that whole thing is a genius!
I added more acid last night before it had a chance to come back up so we will see where it is today. I just thought after 1.5 gallons I would have moved TA from 150-100 but it seems hard to move. If I get it down to 130 or so I think I will leave it alone. We have had a lot of rain over the last week too.
Thanks all!

 

[E Murph]

Today it was sunny all day. Here are my results
FC 5.0
CC 0
TA 125
PH 7.2
CH 225

I still have to fountain running. My thinking is to leave it alone and let the PH come up on its own and leave the TA where it is. Or should I hit it again with some acid? Will the TA keep going down since the PH is still low? Or do I see my TA drop soon after adding the acid? I was happy to see it drop even if just a little bit.

Thanks!

 

[Richard320]

Leave it alone for now. The pH is already as low as you should go. The TA is also as low as it's going to get with this addition. When the pH is down, so is the TA. Pretty much as soon as it's all mixed. Aeration will push the pH back up so you can lower it again and reduce TA some more, but it'll do that on its own given enough time. You're not in danger of scaling, so take a day off.