I use 15% chlorine and also find the PH constantly rises and have to use a lot of acid to counter this rise. Keep an eye on your ALK though because high acid usage will lower your ALK leading to PH bounce, so have plenty of baking soda available.
If you just let your TA get low, then the rate of pH rise and especially the amount of acid needed should drop. Even at a low TA of 40-50 ppm, you should not get "pH bounce" when using a hypochlorite source of chlorine unless you are referring to the rise and fall in pH when chlorine is added and later consumed. There won't be much getting into the water that is acidic so the tendency will be for the pH to rise, though not as quickly. If you want to have additional pH buffering, then you can use 50 ppm Borates. You will also need to raise your CH and/or pH target levels if you have a plaster pool (i.e. to make the saturation index closer to 0).Freelancer said:I use 15% chlorine and also find the PH constantly rises and have to use a lot of acid to counter this rise. Keep an eye on your ALK though because high acid usage will lower your ALK leading to PH bounce, so have plenty of baking soda available.
If the amount of acid per time (per week, for example) is the same at TA 45 ppm as it is at, say, TA 65 ppm, then the higher TA would be fine, but if the lower TA uses less acid then just leave it there. At some low TA you should find that adding acid to maintain pH doesn't lower the TA anymore. At this point, your acid addition is exactly compensating for the "excess lye" in the chlorinating liquid and the carbon dioxide outgassing is minimal. I find it hard to believe that at a TA of 45 ppm that you've got much carbon dioxide outgassing which is why I think your chlorinating liquid may have more excess lye in it than most.Freelancer said:I am currently experimenting with the pools to find the ideal amount of acid/sodium bicarb to firstly lower the PH and raise the alkalinity. So far I have found that in 240,000 litres of water, 10 litres of 15% acid and 10Kg of Sodium bicarb will lower my PH by 2.5 and raise my Alkalinity by 25. I did this to a pool whose PH was 7.85 and ALK 45.
susa said:>>.. pointed out to him that on the label it stated 15ml of chlorine per litre which equates to a 15% chlorine solution he was not convinced because him being the only person selling 90% chlorine was his big selling point
1 Liter = 1000 Milliliters
1 Milliliter = 0.001 Liters
15 Millileters = 1.5 %