With the system tested and no leaks or other problems found, the next step was to make up the saltwater and add the substrate.
Leaving the system fully running, we first mounted and turned on the two powerheads. After that we added the salt to the fresh water already in the aquarium and let the system mix it. As the salt dissolved and the water became clearer, we checked the salinity, adding and mixing more salt until we reached the desired 1.024 ppm reading.
- Salt Mixing Tip: When using this method to make up saltwater in an empty new aquarium, a large pile of salt will usually settle on the bottom. You can just let it dissolve on its own, or periodically stir it up to quicken the mixing process.
Next we added the substrate. To save money we chose not to use live sand, but before dumping the reef sand into the tank, it was rinsed thoroughly in fresh water to remove the fine sediment that mediums like this can contain. As you can see from the photo, adding reef substrates can cause quite a sediment storm. All that can be done at this point is to let the system run and allow the water to clear up on its own, which in some cases, depending on the efficiency of mechanical filtration, may take a day or two.
- Substrate Sediment Removal Tip: After the substrate has been put into the aquarium, as the water starts to clear, it's not unusual to see a fine layer of sediment settling on the bottom. The simplest way to help get rid of this residue is to stir up the substrate, wait and let the water somewhat clear again, and just repeat this process until the clarity of the water is to your satisfaction.
- Pre-Filter Material Cleaning Tip: It is best to rinse out any mechanical filtering materials being used after this type of process. Heavy amounts of sediment will clog the mediums, which in turn reduces a filter's water output rate and filtering efficiency.