Well, i go to home depot and buy the 4 foot by 6 foot insulation foam, and either lay down premade sheets of Grass from the hobby shop(they happen to be 4x6),Or buy Shakers of Grass to give my water some texture, then spray paint the whole thing with blue, then add lighter colors of blue in certain areas, I also make islands out of the same foam cut into shapes and flock those with the Grass.My entire Garage is one big ocean basically. These are done in the 4x6 sections so you can geomorphically add a section anywhere you want to make a bigger ocean.hehe, my wife hates it, cause we park both our cars in the driveway, ive completely turned my garage into a gaming center 
