i have been keeping all kinds of fish and inverts for years now. freshwater, saltwater, brackish water...corals, but i have yet to dive into planted freshwater tanks. could someone give me the basics of highlight, and lowlight, hardwater, and softwater plantings? i have a general idea about the plants, however i am cloudy on CO2 dosing. how do you know how much and how does it work exactyly? is this supposed to be in addition to fertilizers? what problems should i look out for? any info at all will help. ive looked a different websites and book, but i can find any clear deffinitions. i will be setting up very very large aquariums.500-3000 gallons. any info on smaller system planted tanks would be nice as well.