how to make a good cement batch for an upcoming pond project?

hi all i'm really new to this. i dont know what is a good ratio to mix
to get a good cement texture. i will be getting my supplies from home
depot. i'm trying to make a waterwall and pond for my back yard. i
have been reading around this newsgroup and some guy said you have to
seal the concrete with some kinda seal . this is what he said. "If I
remember my old cement pond making days correctly, when the
cement has apparently 'cured' you can brush a solution of water and
sodium silicate over all surfaces, when that soaks in and dries it
seals all surfaces considerably" what is sodium silicate?? i tried
asking the guy at home depot and he looks at me funny . go figure. any
help will be great.....

newbie ponder