go to advanced search and change it to search for "thread titles only" and type seltzer. millions of threads on it. they all pretty much say the same thing so i'm not sure if anyone has anything new and useful for you, but a lot of good stuff on it has been covered by some fancy pants growers so far. i was going to try it this grow but i read a lot about the ph of seltzer being very very low so i think i'm just gonna get a paintball co2 can. should be no problem mixing weak ferts into it. people foliar feed using plain water, but i don't know if the mixing process releases the co2 or what. it just seems inefficient from what ive read.