Extremely high Alkalinity in Indian home pool

Problems relating to pH and total alkalinity.
Increase ph, increase TA. Reduce pH, reduce TA.
pH chemistry advice and techniques for the pool.
sesha

Extremely high Alkalinity in Indian home pool

Postby sesha » Tue 09 May, 2006 03:17

I just started my home pool 10 days ago in India. The color and clarity of the water looks good. I am comforatably swimming, Chlorine looks OK.

However, my test kit shows alkalinity of 560ppm. pH seems to be about 7.8

The pool volume is about 70000 litres (about 18K gallons)

The pool calculator shows 44 litres hydrochloric acid to be added to my pool to bring down the Alkalinity to about 120ppm.

Is it safe to add that much of acid ? I do not think I will add in one go, Can I do it over a week ? Like 6 or 7 litres a day ?

Any advise is highly appreciated...

:cry:


John

Postby John » Sun 04 Jun, 2006 11:59

When adjusting total alkalinity, you will also adjust pH. This is just the way it is and it can't be avoided.

I would never advise to adjust any thing all in one shot. There is always a danger that you will overshoot and then have to try to adjust in the opposite direction.

Also, adjusting alkalinity, especiall extremely high or extremely low ranges, should be done over (possibly) several weeks. You also don't tell us what the hardness of the water is. My opinion is that you should adjust that first. Again, if hardness needs adjustment upward (200-400 range) it should be done in two to four doses. This one is tough because if you overshoot, the only way to adjust downward is to dilute the water (meaning draining up to one third or one half the water and replacing it). If the hardness is in the correct range, then go ahead and adjust the alkalinity.

To adjust the alkalinty, use the acid in several doses one day apart checking before each additional dose. However, keep in mind that these adjustments will affect the pH and you will need to adjust that as well (also, slowly). The pH is important because you always want a sanatized pool. if the pH is low, your chlorine will not work as it should and will lead to other problems. Good luck!
sesha

Postby sesha » Fri 09 Jun, 2006 05:19

John,
Thanks for the reply,
I have started treating the problem, I have added about 50 liters (about 14 gallons) of Hydrochloric acid over the last few weeks. Now my reading shows about 150 ppm, which was 560ppm originally. I was checking pH all along, and ensured it did not go below 7.2 when I add acid.

My water hardness is about 470ppm.

I have been observing that once I add acid, next day the pH reads about 7.2, and in a couple days it creeps back up to 7.8+ That is when I add more acid. With this process, I added about 50 liters, I keep observing alkalinity and pH.

I might reach 120 ppm in the next couple days, however, I still see the pH creeping backup to about 7.8 slowly.

Do you think once I reach the optimum level of alkalinity the pH might be stable ? Or is the hardness doing something ?

I do not see anyother problems with the water/pool

Cyanuric acid (Chlorine stabilizer) is not available in India, so I had a friend buy it for me in US and bring it over here, I am planning to add it to the water to protect Chlorine (It is always about 100 degree F to 110 degree F in India) I am using liquid Chlorine, since it is easy to add.

Do you think I can add the Cyanuric acid granules directly into the pool ? Since I have a liner (not tiles) should I dissolve the granules in bucket of water and then add to the pool ?

Tx
sesha

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