Low alkalinity & combined chlorine

[angiedubberke]

I take care of a 2500 gallon splash pad. For the past 2 weeks the alkalinity will not stabilize. I can only get it to be about a 40-50. I have added alkalinity increaser, but by late afternoon my alkalinity is back to about 50. Also during this time I my combined chlorine keeps running about .6/.7. I have been shocking and backwashing, but nothing seems to help. The ph is staying consistent at a 7.4, acid is 25. I am running out of ideas. Is there a correlation between the two issues?

[PoolDoc]

Read the page http://pool9.net/alk-step/

That page explains how to do -- on purpose -- what you are currently doing accidentally.

Bottom line is, it's not possible to maintain a standard pH level AND standard carbonate alkalinity levels.

[CarlD]

I'm not sure why you care about Total alkalinity if your pH is fairly stable. BTW, if you are using pool store "Alkalinity Increaser" you are wasting your money--it is nothing but baking soda, but they label it "Sodium Hydrogen Carbonate" to make you think it is not what it is, which is......Sodium Bicarbonate--baking soda. Sodium Hydrogen Carbonate is an alternate name. You can buy bags of 12-13 lbs at CostCo for about $4....