Before we went on to the next step on making our Opae`ula habitats, Mr. Leong told us that we would be using a hydrometer to check the specific gravity on Seawater (Seawater has a specific gravity of 1.024) and fresh water (freshwater has a specific gravity of 1.000). We used brackish water to fill the habitat. The Opae`ula live in water with a specific gravity of 1.004 but we had the gravity go to 1.006-1.008. Some of our products were decomposers, bacteria, rocks,and producers (which were the shrimps food. we first put bacteria into our habitats. 2) we each picked our rock then we watched Mr. David pour faucet water into a bucket and mix it with a type of salt called Instant Ocean sea salt. the first time it was too salty. the second time it barely was okay to accept because the specific gravity was 1.008.6) Then we poured the water we made, into our habitats. we filled it up halfway. AND THAT WAS IT.