Sue

No, my husband and I had a competition to see which forum gave us the quickest reply! Sue

I needed to increase my Total Alkalinity levels - they were Lo on the Scuba+ reading. Other readings were as they should be: Free Chlorine 2.4 Ph 7.4 Cyanuric acid 23 So started adding Sodium Bicarbonate to increase TA..... .....and added some more sodium bicarbonate.....and added some more sodium bicarbonate all to no avail. I've added about 12kg to a 75,000 litre pool which should be enough! So I did some research and wonder if I have discovered my problem? I use a Chemigem controller and dose the pool with liquid chlorine and sulphuric acid and I'm wondering if it is the sulphuric acid which is causing the problem? The research suggested that sulphuric acid is very aggressive at reducing alkalinity but Hydrochloric acid much less so. Is that the solution to my Alkalinity problem - change to Hydrochloric acid and add (even) more sodium bicarbonate? AND if so, is it simply to just change acid in the Chemigem or will I need to remove some water from the pool and replace with fresh water as well? Thanks as ever for the very helpful info posted about swimming pools - I'm hoping you can advise on this one as well! Sue