Hi all. I live in Singapore where we have high temperatures and high humidity. Some leave load, but not much as I scoop daily.
I have a lap pool, and 2 years ago I switched it from a chlorine pool to a no-chlorine pool and from getting a pool guy to come in twice a week, to self maintenance.
I now use an Australian invented system that uses silver and copper ions and an oxidiser to sanitise the pool.
Target copper level is about 0.3 ppm.
Since I switched, I have had problems keeping the pH balance. I add sodium bicarbonate to raise TA, then dry acid (sodium bisulphate) to lower pH.
pH will not stay low. It used to rise about 0.1 every day, so within a week it would go from 7.4 to more than 8.0. So I found myself adding a lot of bicarbonate each week, followed by a lot of acid! My target was to keep TA at about 80, and pH at about 7.4. But I was, and am, using tons of bicarbs and dry acid.
Initially, I had little calcium hardness, and raised the CH to 200 ppm on recommendation of the supplier. That did not help. Now my pH rises even faster, by about 0.2 a day!
I recently googled and read some exchanges on this forum about out gassing of CO2, which gave me some new theories about why my pH is rising.
The suggestion in that thread was to maintain pH at a higher level - say about 7.8, instead of trying to force it lower, and to maintain TA at a lower level of 50 - 70, to avoid outgassing.
However, the manufacturer's recommended pH is 7.2, and warns that the effectiveness of the sanitiser falls sharply if pH rises about 7.6. I have read elsewhere that this is also the same for chlori
So I face a dilemna. If I don't fight the pH, but keep it at about 7.8, I will use much less acid, and the TA will probably fall off slower as result. So I would not need to use as much chemicals.
But then I am concerned that my sanitiser would not work effectively, because it is outside the manufacturer's range!
Has anyone experienced similar problems, and any suggestions on how I can stabilise my pH at about 7.4?
Some other info:
When adding sodium bicarb, I have had, from time to time, blue precipitates in the water. I think this is some copper salt, and suggests some saturation of carbonates in the water.
But I don't understand the water chemistry enough to figure out the right regime to maintain pH.
What am I missing here?
Also, I calculated my Saturation Index as follows: pH + TF + CF + AF – 12.1
TF at 86 degrees F is about .7
CF at 200 is 1.9
AF at 75 is 1.9
So at pH 7.4, my SI is -0.2
and at pH 8, my SI is +.4
This is supposedly indicative of balanced water.
Thanks in advance for any responses!
David
I have a lap pool, and 2 years ago I switched it from a chlorine pool to a no-chlorine pool and from getting a pool guy to come in twice a week, to self maintenance.
I now use an Australian invented system that uses silver and copper ions and an oxidiser to sanitise the pool.
Target copper level is about 0.3 ppm.
Since I switched, I have had problems keeping the pH balance. I add sodium bicarbonate to raise TA, then dry acid (sodium bisulphate) to lower pH.
pH will not stay low. It used to rise about 0.1 every day, so within a week it would go from 7.4 to more than 8.0. So I found myself adding a lot of bicarbonate each week, followed by a lot of acid! My target was to keep TA at about 80, and pH at about 7.4. But I was, and am, using tons of bicarbs and dry acid.
Initially, I had little calcium hardness, and raised the CH to 200 ppm on recommendation of the supplier. That did not help. Now my pH rises even faster, by about 0.2 a day!
I recently googled and read some exchanges on this forum about out gassing of CO2, which gave me some new theories about why my pH is rising.
The suggestion in that thread was to maintain pH at a higher level - say about 7.8, instead of trying to force it lower, and to maintain TA at a lower level of 50 - 70, to avoid outgassing.
However, the manufacturer's recommended pH is 7.2, and warns that the effectiveness of the sanitiser falls sharply if pH rises about 7.6. I have read elsewhere that this is also the same for chlori
So I face a dilemna. If I don't fight the pH, but keep it at about 7.8, I will use much less acid, and the TA will probably fall off slower as result. So I would not need to use as much chemicals.
But then I am concerned that my sanitiser would not work effectively, because it is outside the manufacturer's range!
Has anyone experienced similar problems, and any suggestions on how I can stabilise my pH at about 7.4?
Some other info:
When adding sodium bicarb, I have had, from time to time, blue precipitates in the water. I think this is some copper salt, and suggests some saturation of carbonates in the water.
But I don't understand the water chemistry enough to figure out the right regime to maintain pH.
What am I missing here?
Also, I calculated my Saturation Index as follows: pH + TF + CF + AF – 12.1
TF at 86 degrees F is about .7
CF at 200 is 1.9
AF at 75 is 1.9
So at pH 7.4, my SI is -0.2
and at pH 8, my SI is +.4
This is supposedly indicative of balanced water.
Thanks in advance for any responses!
David
