Your question piqued my interest this morning and while I haven't ever run reef tanks, my random trolling for information led me to a reef tank forum anyway. Here's a discussion where some folks were debating between biopellets vs vodka dosing.. Biopellets and Liquid Carbon dosing - Reef Central Online Community
. In this thread and a few other hits, I interpreted the grain of thought that the bio pellets are a controlled source of "slow release" carbon. One post even went as far as to suggest that the carbon and bacteria "business" of the reactor shouldn't even escape the reactor to get into the rest of the tank. Whereas, the vodka dosing, they can overload and flush the entire tank full of carbon for bacteria to grow everywhere.
Now, I'm making a pretty big jump to conclusion, but from my non technical standpoint, I feel like this method wasn't meant to supply nearly enough the carbon that we need in our tanks. It was created to raise some bacteria. We need enough to raise plants. What would be the amount of media that you would need to get the necessary amount of carbon into your tank?
Anyway, if you're looking for a safer method of carbon dosing, how about the old diy method with sugar and yeast or even cooler now the vinegar/citric and baking soda method (https://www.plantedtank.net/forums/20...-soda-co2.html
). You could get a premade kit nowadays that looks pretty nice.
Who knows, you may even start the grandkids interest early in chemistry!
Having said all that, pressurized co2 is not as dangerous as it sounds as long as proper safety precautions are observed. Mostly, use good products and avoid a situation that allows the tank to tilt or fall. Even with DIY methods you have to worry about ingestion risks, etc. But if you're not comfortable with it, you're not comfortable. Peace of mind is important in a hobby