Close call...

Had my first close call today with CO2. I bought a Fluval CO2 Indicator last night and this afternoon I noticed it was indicating that I wasn't dosing enough CO2 into the tank. So I turned it up a little bit. Like 1bps more so it was going at about 2- 2.5 bps. A few hours later I look in the tank and the indicator is yellow and my 2 plecos are pretty much lifeless. One was barely moving and the other was literally belly up. I put them both in my other tank hoping the one that was still moving would perk back up but thinking the other was dead. Thankfully 5 minutes later the one that was moving perked right up and started munching on algae in the tank. Ten minutes after that the other one was doing the same. Tetras all seemed fine even with the high CO2 in the tank. I did a 25% water change, turned up the airstones to full and turned off the CO2. Once the indicator goes back to blue I will put the plecos back in the tank. Should I maybe keep them in the large tank until the CO2 is under control to play it safe? I like those little guys I would hate to lose them.