Our trip to this crystal temple will be pretty brief. Unlike the Temple of Wind there are no enemies here at all, nor a boss at the end, so relax. The layout of the temple is identical to the Temple of Wind too, except there are no upstairs or downstairs.
If you're curious, inspect the rooms to learn more about the temple's state. You'll also find a number of chests, in the bottom-left corner ( Remedy ), top-left corner ( Ether ), top-right corner ( Ice Charm ), bottom-right corner ( Phoenix Down ), left from the top-right corner ( X-Potion ) and left from the bottom-right corner ( Hi-Potion ).
Once you've seen enough of the temple, head straight up from the entrance, where the Adventurer and the exit awaits. Through the exit, you'll be in front of the altar of water as well as the Water Crystal. Though the crystal here is just as dull as the Wind Crystal once was, the difference is that there's a magical barrier surrounding this one.
While Agnes can dispel the barrier just fine and awaken the crystal, she wishes for Olivia--the Water Crystal's vestal--to perform this sacred duty instead. Trouble is Olivia has gone AWOL and the Temple of Water offered absolutely zero clues of her whereabouts. Guess there's nothing to be done besides heading back to Florem to report your findings to the Matriarch.