Alkalinity keeps rising

wkussmaul

Gold Supporter
LifeTime Supporter
Aug 29, 2010
45
#1
Hi all,
My trouble-free pool is doing great under the BBB method, in general.
However:
I have noticed that the TA is high (tends to want to be ~125-130).
I add acid. Ph and TA go down, then I aerate to a higher pH-- at which point the TA is right back up there again.

Here are a series of test results (CH constant at 270, CYA 46, FCL/TCL hovering 2.0-4.0 as I add daily bleach):

day 1: pH 7.6 TA 134 => add acid
day 2: pH 7.0 TA 89 => aerate for a day
day 3: pH 7.3 TA 84
day 4: pH 7.4 TA 125

It's as though there is a source of alkalinity; like my 4-year old plaster is still curing, or something.
Is this a problem? Or do I just keep adding acid?

:?:
 

coffeegoddss

LifeTime Supporter
May 12, 2012
94
Minooka, IL
#2
I don't know about the plaster but have you tested the water you put into the pool? I battle high TA and, for giggles, decided to test what comes out of the hose. The TA was 290! So every time I top off the pool an inch or two, I'm adding to the TA. It's a never ending battle - but I think I've finally gotten it under control. Now that I know what's causing it, I can correct it pretty quick.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
#3
Have you been adding water to top off the pool? Fill water is a common source of TA in some areas.

Lowering TA is a fairly slow process. Give it time and it will work.

Also, what test kit are you using to get those test results. None of the tests which give results +-1 are actually any where near as precise as they imply that they are, and you actual levels are likely to be noticeably different than the results returned by those tests.
 

HouTex

LifeTime Supporter
Mar 7, 2011
413
Houston, Texas
#4
Similar issue here. Just this week my TA went from 50 back up to 70 over a 5 day period with NO added water. I wonder if a temporary drop in TA is normal after an acid addition? My TA will always drop 10 to 20 ppm about a day after an acid addition. Two or three days after that it's back up, but it does not continue to rise above 70. I can't imagine it's a problem with my circulation. With my 2 HP pump I get a complete turnover every 1.5-2 hours.
 

JulieS

Well-known member
Jun 17, 2012
55
Michigan
#5
I just asked this same question in another thread! I am not adding water at all, once my TA is in range, a day later it is back to 170-180. The TA of the water I used to fill is 270, but once I get it down, shouldn't it stay down? I understand that if I add more water it will go up, but with just normal conditions it shouldn't... right?

I have had to back fill one time, I used a standard garden sprinkler to aerate as I filled, it helped bring my pH up so that I could add the acid to lower the newly raised TA!
 

wkussmaul

Gold Supporter
LifeTime Supporter
Aug 29, 2010
45
#6
To all who replied,
Thanks.
I will test the fill water, should have thought of that.
But, in the above series of test results, no water was added.
My tester is the Lamotte ColorQ.
 

dschlic1

LifeTime Supporter
Oct 5, 2007
560
Valrico, FL
#7
I have noticed that if it rains after a period of dry weather, the TA in my pool will increase. I believe it is the dust and diry washing off of everything.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
#8
The ColorQ's alkalinity test is +-15 in the relevant range when everything is working correctly.

I suspect the Day 4 result might be wrong. It will be interesting to see if that increase continues or the number drops down the next time you test it.