pH to high after adding baking soda to raise TA - Help Please

[myLABSpool]

Hi,
So I opened my pool a couple weeks ago and circulated the water for 4 or 5 hours and tested, and here is what I had.

FC - 0 (I had not added any since closing in fall)
TC - 0
pH - 7.0
TA - 70
CYA - 20

I shocked to 12 PPM (following guidance of best guess chart) and held it their for several days to clear the water as it was cloudy and a little green. The water is crystal clear now and no signs of algae.

Also during this period, I wanted to get my TA up, so I used the Pool Calculator. For 24K gallons of water it said to add 11 lbs (I added 10 lbs) of Baking Soda for a TA of 100. So I added 10 lbs all at once. The next day I tested, my TA had gone from 70 to 140! The pH was now about 7.2.

Now over the course of about the last 10 days, my TA has settled around 110 from the original TA of 140 12 hours after adding the baking soda which is fine. However my pH has crept up to 8.0 from 7.0!

So I'm a little confused as to why my TA went too high initially and why is my pH going so high at 8.0 and what should I do about it?

My pool tested yesterday afternoon as;
FC - 5.0
TC- 5.0
pH - 8.0
TA - 110
The water still looks perfect.

I have 24K gallon vinyl liner
sta-rite heater and sand filter.

Thanks
Andy

[CarlD]

Baking soda can raise your pH. I would simply add acid to bring it down. You don't list your CYA/stabilizer so if that's low the easiest way to add acid and stabilizer is tri-chlor pucks--but just temporarily until you hit desired levels. Or you could add either dry acid or muriatic acid until it's right.

You have a vinyl pool so too-high T/A is not any problem unless it reaches about 200ppm AND your Calcium levels reach about 400-500ppm.

I wouldn't be concerned.

But there's a lesson to be learned here: Unless it's chlorine, NEVER add any chemical to the full amount recommended. Always add part and wait, then measure, and then add more IF NEEDED. Otherwise you will find yourself over-shooting your desired goal again and again.

With chlorine, the biggest risk of adding too much is bleaching your liner, but that's about it.

[aylad]

I realize this is not the case here, but also keep in mind that you don't want to dose your pool with anything when it's at shock level--high levels of chlorine can give falsely high results with pH and TA testing, depending on your testing method, and cause you to overshoot your doseages. Also, you might find that the rise in pH that occurred when you added the baking soda can be temporary--often it will rise but then partially lower again as it all "settles" in the pool. It's generally better to dose your pool with one chem at a time, and like Carl said, creep up on your target dose instead of going all at one time. Patience is the key!!

Janet

[myLABSpool]

Thank you for the help. My 8.0 pH has slowly crept back to 7.6 without adding any acid and my TA is 110, so I'm very happy.

[mja351]

i think that u should've adjusdted your ph and ta before shocking