If seawater is unavailable, you can find salt water aquarium mix at any pet store that sells salt water fish.
(seawater; is; unavailable) (you; can find; salt water aquarium mix; L:at any pet store) (any pet store; sells; salt water fish)
seawater you any pet store
is can find sells
unavailable
salt water aquarium mix L:at any pet store
salt water fish