Its been variously stated that pH change from differences in CO2 do not negatively impact fish health.

Does it follow that that if one has a quaranteen tank with non-co2 but same substrate etc. as the main Co2 tank, that you can just net and dump the new fish from Q-tank to main tank - with no/minimal acclimation to the main Co2 tank?

Assume water source = same.

Thanks,
growitnow

Anytime you move fish from one tank to another tank I think you should acclimate them to the new water. The water can be considerably different in two side by side tanks that you have tried to treat the same way. It shouldn't take very long to acclimate them, but I wouldn't just net and release in the new tank. (However, I have done just that, with cheap guppies, and had no problems.)

I would drip acclimate for 30 mins. I have seen fish gasp at the top going from a non-CO2 tank (.99 cent neons) to a CO2 tank. In thie case the CO2 tank was at least 30 ppm. The other tank ambient CO2 levels. Plus tap can vary. The KH from my tap varies between 2-6KH, and a large difference in KH is likely to stress fish.