PetroBoomN

This is great info thanks. I knew dissolved CO2 can lower pH, didn't consider there could be other gasses in my water that could artificially boost pH. Something the City water department said actually rings a bell now, I can't remember what the chemical was, but the guy said they used some type of gaseous chemical to disinfect their water rather than chloramine. I will fill some buckets and let them sit 2 days to see...

I had tropical fish for many years while living in the Chicago area and never had issues with water parameters. Water was hard, but the only thing I ever did was add Catapa leaves when I had Apistos and that worked to lower pH a pinch. I now live in Southern Ohio and my municipalities water is very whack. Tap water pH: 9.0-10.0 KH: 30-35 ppm GH: 150-300 range. I have called the city and they confirmed they target 9.5 pH and they don't measure KH at but he said they use limestone filters with the goal of removing "as much if not all carbonates" they also do nothing to reduce the naturally high GH. So enter my two current tanks: 20 gallon long and 15 gallon fluval cube. 20 gallon has Fluval stratum which drops my KH down to undetectable <10 ppm and pH down to 6.5. The 15 gallon has UNS Controsoil which brings my pH down to 7.0 and does not reduce KH at all. The substates seem to reduce pH (and KH on the Fluval stratum) over 8-12 hours, as I have tested my tank just after water changes and 20-25% WC usually jumps my pH up 1.0-1.5 points. I hate this because I'm afraid to do larger WCs which are sometimes necessary. The other issue I am having is the 20 Gallon has been running for a month and has 13 fish and an army of snails. My pH is slowly dropping 0.1-0.2 points per day. Since the tank is planted my Nitrates never read over 10ppm. I'm guessing this is do to extremely low KH. I do W/Cs and my pH and KH jump up, then drop back down to <10 ppm KH and 6.5 pH hours later. How can I raise my KH without also boosting my already high GH in the tank? I'm really looking for advise on how to manage and deal with my tap water long term. This water is honestly just not conducive to fish keeping it would seem (despite having 0 chloramines). I hate that every water change is a small shock to my fish when it should be a refresher. I have never done salt water so I know nothing about remineralizing RO water, but I have recently bought an RO filter for my house just to have better water for my family. Advise? I'm open to any similar stories or pointers.