Lo-Chlor Chemicals – Solutions of swimming pool and spa problems

01639 823 233 | paul@totalwaterproducts.co.uk

Lo-Chlor UK – Troubleshooting Guide 1
Water Balance Problems:

1. Symptom: pH too low (below 7.2)
Likely Cause: This is actually due either to low pH of the supply water (especially in soft water areas) or to the use of an acidic chlorine donor, such as trichlor tablets.
Remedy: Correct the pH by raising it. To raise the pH, add Soda Ash (pH Plus) at a rate of 1kg per 100m3 (100,000 litres/22,000 gallons) of pool water daily until the correct reading is obtained. You may also consider changing to a higher pH chlorine source to help achieve a natural balance between the low pH of the source water and the high pH of the chlorine donor. Dichlor is roughly pH neutral and both Calcium Hypochlorite and sodium Hypochlorite are high pH chlorine donors.

2. Symptom: pH too high (above 7.6).
Likely Cause: This is due to either (i) high pH of mains water (especially in hard water areas) or (ii) to the use of high pH chlorine donors such as Calcium or Sodium Hypochlorite or (iii) to hardness salts being leached from new concrete or mosaic pools.
Remedy: The remedy is the same irrespective of which factor is at work here – that is correct the pH by lowering it. To lower the pH add Sodium Bisulphate (Dry Acid/pH Minus) at a rate of 800gms per 100m3 (100,000 litres/22,000 gallons) of pool water. To add pre-dissolve in a clean plastic container, at a rate of 100gms per 5 litres of water, spread evenly around the area of the pool. Re-test the water after 2 hours and repeat if necessary. For (i) and (ii) consider changing to a low pH chlorine source to help achieve a natural balance between the high pH of the source water and the low pH of the chlorine donor. Trichlor is the obvious chlorine donor to use. For (iii) the difficulties with new concrete pools will clear up of their own accord given sufficient time.

3. Symptom: pH values are erratic and fluctuate (pH bounce).
Likely Cause: The reason will be that the total alkalinity levels of the pool water will be too low to buffer the pH.
Remedy: The remedy is to raise the total alkalinity in the desired range of 80 – 150ppm. To raise the total alkalinity add Sodium Bicarbonate (Alkalinity Increaser) at a rate of 3kg per 100m3 (100,000 litres/22,000 gallons) of pool water. Re-test the water daily and continue to add until the correct total alkalinity range is achieved.

4. Symptom: pH is "locked".
Likely Cause: The pool water is over buffered due to high levels of total alkalinity. This is not uncommon in hard water areas where the mains water has high levels.
Remedy: The remedy is to lower the total alkalinity to within the desired range (see above). This can be achieved by using (i) Sodium Bisulphate (Dry Acid/pH Minus) or (ii) Liquid Hydrochloric Acid (TA Reducer 20%). For (i) To lower the total alkalinity by 20ppm add 4 kilo's of Sodium Bisulphate, per 100m3 (100,000 litres/22,000 gallons) of pool water. First turn the circulation pump off, pre-dissolve in a clean plastic bucket, at a rate of 500gm per 5 litres of water, and add at one point in the deep end of the pool. Leave the circulation pump off, for a minimum of one hour, and then re-start the pump. Wait a minimum of 30 minutes before re-using the pool. Re-test after 24 hours and repeat if necessary. For (ii) To reduce the total alkalinity by 10ppm follow the same steps with your circulation pump and add at a rate of 2.2 litres per 100m3 (100,000 litres/22,000 gallons). Leave the circulation pump off, for a minimum of one hour, and then re-start the pump. Wait a minimum of 30 minutes before re-using the pool. Re-test after 24 hours and repeat if necessary.

5. Symptom: Alkalinity too low.
Likely Cause: The incoming mains water is low in bicarbonates therefore whenever the pool is topped up from the mains water (for example post backwashing), it dilutes the bicarbonates in the pool. This is a particular problem in soft water areas.
Remedy: Add Sodium Bicarbonate (Alkalinity Increaser) to raise the total alkalinity to 100ppm. The dose rate is 3kg per 100m3 (100,000 litres/22,000 gallons) of pool water per day (this should raise the level by 20ppm in 100m3 per dose).