Carbon Dioxide Aquarium Plant Food CO2 LIQUID

Initial cost of a CO2 setup is about $140 US, $10 a year after that for a
decent size tank. You can run multiple tanks off one cylinder so maybe 3
tanks running for $10 a year... some of these other methods seem cheaper at
first glance, but over a year or more there is no difference, not to mention
that a compressed system is easily controlled, simple and effective. Why
pay more over the long run for something that is inferior?

Cheers,
Jeff Ludwig