I have an in ground pool with SWG and more recently a pHtek automated acid system. Prior to the pHtek I always had an issue with high pH and high TA thanks to the SWG. After the pHtek was installed the pH has always been spot on. I also have a waterfall, so the addition of acid and aeration also kept the TA where I want it.
Recently however the TA has taken a nose dive down to 20, vs my target of 70. Now I'm looking at adding Soda Ash to get that back in line.
Is this common or do I have an issue I need for remedy? It seems counter intuitive to add both acid and soda ash.
Thanks in advance for any advice.