I kind of liked this episode. I'm not a huge season 5 fan, but this one was exceptional. Parts of it were funny (like Spongebob: Patrick, that's Squidward. He's not gone, he's right here.
Squidward: (planting flowers) No, I'm not. (walks inside)) but some were weird like the ending (Spongebob: Is this how we're going to spend the rest of our lives? Living in fleas instead of water?
Sandy: Spongebob, that's it... water! (puts on a water helmet and karate chops her way through the fleas and opens the door to cause the whole ocean water to come rushing into her dome and the fleas to disappear)
Spongebob & Patrick: Water! (all the fish and water comes pouring into her dome and causing everyone to be squished inside against the glass)
Spongebob: (through glass) It sure is good to have you back, Sandy.) Overall, a pretty good episode. 7/10.