Buffering for co2

Hi all, I have a couple of low tech aquariums, and wanted to increase my growth of the plants I enjoy in those tanks, but I wasn’t quite ready to dive into the (in my opinion) scary world of fertilizer dosing and CO2 injection in tanks that I had livestock in. So as a way to dip my toe in ,I grabbed a 5 gallon bucket, set some nice grow lights on top, got a very basic CO2 system, and have been dosing liquid fertilizers that I use for other plants around the house, like pathos and such. I’ve only been doing this for about a week but I have seen some noticeable growth in several plants, even ones like Anubis. My question and concern comes from the drop in pH, it seems to be around 5 1/2 even after the CO2 has been off for several hours, I’m definitely overdosing in that respect and have kept the CO2 off since then, with it not raising back up after a day. Are there any tips that anyone has that could help me out with keeping the pH in a more stable area, with buffering and such? Am I doing something completely crazy here and going kill all of my plants? Any tips or resources I should be looking at would be helpful, I’ve read quite a bit of this subject over the past couple of weeks, but I’m sure there’s lots I’m missing and have to learn.