What's the difference between Total Chlorine and Free Chlorine in a salt water pool?
Got a new test strip kit today (brand: AquaChek Pro) and have a few questions:
It says that my Total Chlorine is within range, but the Free Clorine Level is a bit low.
How can I improve the Free Clorine level (now 0.5 - 1.0) , the recommendation say 1.5 - 2.0), or can I ignore that?
FYI: pH is always a bit on the high, normally in the 7.8 range (should be around 7.2)
Please advise.
In a very simplistic answer;
Free (available) chlorine is the the chlorine available to sanitise the water (kill bacteria) It is the important one.
Total chlorine is the sum of all the chlorine compounds in the water. The compounds result from having killed bacteria or combined with human waste. These compounds give the "chlorine smell" to the water.
In an ideal situation they are the same.
The best way to fix this is to "super chlorinate" the pool. This involves raising the chlorine level to about 8-10ppm. It oxidises the waste products. The best time to do this is when everyone has finished with the pool in the evening. In the morning the pool will sparkle and will not smell of chlorine in spite of a relatively high chlorine level. I usually use about 500g of powdered chlorine per 40- 50,000l
The pH is high. Salt water chlorinators and some chlorines tend to make the pH go up by their nature, you will find that you will need to add acid on a fortnighly or even weekly basis. It depends on a number of variables including sanitation method, amount of use, filtration, and the amount of foreign material blown into the the pool.
When the pH is high the chlorine is less effective as a sanitiser. You need to add acid roughly 200ml per 25,000l. I usually add the acid to a bucket of pool water and pour it around the edges of the pool with the pump running, brush the walls of the pool and then "super chlorinate".
DO NOT mix chlorine and acid in the same container, the result is chlorine gas. VERY unpleasant.
