When I lived in Southern CA. The LFS I went to used Ocean water but it was collected about 30 miles off he coast then they filtered the water. With out a doubt that was the best water I have ever used. Just my 2 cents.
I use NSW... local university has a research station at the beach and provides filtered and UVed water and raw....been using it for some time with little to now issues... plenty of SPS in my tank just being happy campers... I do always verify salinity and sometimes have to adjust... also I use the filtered but add the raw from time to time
Note: I think it is filtered 25 micron... and i do my water changes through my gfo in case phosphate is a concern... (it can be higher then sps like seasonally so always check)
I occasionally do water changes with natural ocean water I collect at the beach (a clean one). I do it primarily for the bacteria and other organisms that come with it, so I use it right away and do not treat it at all.
Natural seawater can be a fine source of water for a coral reef aquarium. Many aquarists collect it themselves if they live near an ocean. The most important factors are how pure it is when collected, and how pure it remains until used. It is often suggested to collect the water offshore to avoid run-off and other pollution sources although even offshore waters can have unwanted organisms and chemicals in them. The next best is to collect it from a rising tide from a jetty or other means, to get a bit away from shore. There can be risks to using coastal waters. Depending on the location there could be enough chemicals or pathogens to harm the tank. Also, even far from shore there may be elevated nutrients and salinity that deviates significantly from “pure” seawater.
One issue with natural seawater is that it contains suspended organic molecules, bacteria, phytoplankton and other organisms. In most cases, these will not hurt an aquarium and may actually provide food for many reef aquarium inhabitants. But if the water is stored and allowed to stagnate, the breakdown of these organic materials can produce toxic compounds such as ammonia and hydrogen sulfide. For this reason, storing natural seawater is usually preceded by filtration, and even sterilization processes in some cases. It is beyond the scope of this article to detail these procedures, but aquarists storing natural seawater should be aware of these concerns and seek out additional resources to deal with these issues. For those interested in further details, Martin Moe mentions how to treat and store seawater in his Beginner to Breeder book and also his Marine Systems book.
One word of caution is in order. Some companies collect and sell natural seawater. However, it appears that in some cases this water is not handled as well as it might be. One company, for example, has had significantly elevated lead and zinc in its water, suggesting possible exposure to metals in the collection or handling process (see analyses studies linked below). Consequently, not all “natural seawater” is the same.
That's all I use. I have a good supplier who tests the water before collection and won't collect for a week after rain to be safe. If the levels ain't write he won't collected as he uses it himself and does not want to put he's customers tanks at risk. If your going to collect yourself test it before you do
I have used natural sea water on all my tanks over 25 years, here in Miami that is. The LFS here as well as the distributor trucks sell to customers. I have a boat, and usually pick up around 100 gal when I'm offshore. When it's rough I have collected at the inlet at high tide, same place the trucks that deliver drop their hose. I use the truck service when I am setting up a large tank for a client the first time filled. I agree with what was mentioned above, beware of stored water! Some LFS hold it for too long with no circulation in an outside tank which can get very warm, especially in the summer down here.[emoji4]
Thanks for all the info guys!! Great stuff! We have a place down in key largo and can easily go out 20 miles offshore and grab some fresh salt water. I will research more on storing and filtering the water. Thanks again !
I recently did a water change with ocean water and I noticed some of my corals didn't enjoy the change too much. One of my Shrooms ended up splitting into two. If you started with natural water from the beginning maybe it'll be okay. As the tide is running inshore would probably be best time to collect because you get cleaner water flowing into shore, and also i wouldn't go collecting water from anywhere where the shore is covered in washed in or loose seaweed, or stagnant water.
We have the Scripps Pier here in San Diego which provides free NSW to commercial institutions and hobbyist. Been using it quite some time now for water changes with no problems. The only issue is the dKH of the water is always around 6-7 which I have to bump up some before using it.
I supplement with NSW at a jetty just inside the breakwater at high tide. I bank on the fact there is a variety of organisms suspended in my collected water. Of course I have to make adjustments to the water to match up with my parameters, but it matches up with my philosophy on keeping a reef tank. Honestly I think I would struggle more if I lived "not by the ocean". That means any of the reefers that live in the midwest, I give you props!