You know what, it is always going to be okay. But the more air in your water, means the less co2 that is in. If you are pumping air into the sump, the co2 will get pushed out, and if your return pipes are creating bubbles as well, you will lose co2 there as well.
But not to say that you will not get co2 dissolved into your tank water but that you need to really focus on getting your co2 bubbles dissolved. If you can find a way to get close to 100% dissolved, you should be just fine. But if you are only getting $25 dissolved and you have air bubbles everywhere, you're co2 will not be helping out your plants much.
If you are doing a diy co2, know that you are not producing enough co2 to harm the fish. And that turning on your air only at night (when the lights are off) should be plenty of air for the fish. Sometimes I don't even turn my air on at night.
Also, if you have sensative fish like discus that need lower levels of ph, then air only raises the pH in the tank. And co2 lowers it.
But back to the question, if you can get your co2 to dissolve into the water at a rate of near 100%, the air bubbles you are getting won't affect it much
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