Given the ready availability—and relative affordability—of high-quality synthetic sea salt mixes, it’s not surprising that the vast majority of marine aquarium hobbyists today choose to use artificial sea water rather than collect the natural stuff from the ocean for their systems.
But that doesn’t necessarily mean synthetic salt water is superior to its natural counterpart in all cases. Depending on a hobbyist’s circumstances, collecting water from the ocean can be a perfectly viable alternative. In fact, some hobbyists who use natural sea water in their tanks absolutely rave about the results they see in their livestock.
Obviously, for people like me and Chris, who are located many miles from the nearest ocean, collecting natural sea water is a lot like failure on the Apollo 13 mission—not an option. But for salties lucky enough to live right on the coast, it may be a choice worth exploring.
However, there’s no question that there are certain challenges attendant upon collecting natural sea water. If you’re one of the fortunate few “coastal salties” (or as Chris and I like to call them, “long-lost relatives”), you’ll have to decide for yourself whether any of the following obstacles are deal breakers:
Finding a clean source
There’s plenty of clean water in the ocean, but it’s not always as easy to access as we’d like. The inshore waters you can reach with the least amount of difficulty—e.g., from a pier, dock, boardwalk, boat launch, or beach—are also the most likely to be polluted with marine fuel residue, agricultural runoff, sewage, and other contaminants. That’s why it’s best to collect as far off shore as is practical.
If you happen to own a boat (or know someone else who does and is willing to take you on regular water-collecting trips), traveling off shore to collect non-polluted water may not be a major problem, but if you don’t, you’ll need to find a site within reach of shore that’s less likely to be contaminated. That means an area with:
- Minimal boat traffic
- No rivers, streams, or creeks discharging nearby
- No nearby urban or industrial area
- Stable, appropriate salinity (i.e., not an estuary or other brackish environment)
- A healthy population of marine wildlife
Also, if you must collect close to shore, in addition to the points listed above, try to do so when the incoming tide carries in the cleanest possible water.
There’s no getting around the fact that collecting natural sea water involves some heavy lifting and logistical challenges—especially if you’re collecting for a large aquarium. Five-gallon buckets, heavy-duty plastic bins or trash cans, and similar watertight vessels are the usual tools of the trade for hobbyists who collect their own sea water. Once these containers are filled, lugging them to your vehicle (possibly after hoisting them off a boat) and then into your home can be a real chore.
Treating the water
When mixing artificial salt water using RO/DI-purified water and a quality sea salt mix, all you have to do is make sure the basic parameters—specific gravity, temperature, pH, etc.—are in the correct ranges before using it in your aquarium.
Natural sea water, on the other hand, tends to require a lot more pretreatment before it’s safe to use in aquariums because of the dissolved organics and planktonic life it often contains. This typically involves filtering the water through a micron filter sock at the time of collection to eliminate as much debris and plankton as possible. Then, processing of the water usually continues once the hobbyist gets it home in order to render it safe for aquarium use. This might involve one or more of the following steps:
- Storing the water in a dark container for at least a few weeks to allow any remaining plankton to die off and settle to the bottom, and to allow bacteria time to consume any dissolved organics
- Running the water through an ultraviolet sterilizer to kill off any parasites or disease-causing microorganisms
- Treating the water with chlorine to kill off any life form, followed by the use of a dechlorinator
Of course, after that, it’s still necessary to test and possibly adjust all the critical water parameters to make sure they match the parameters in your aquarium.
Do you collect your own salt water?
If you’re a coastal salty and collect your own sea water, we’d love to hear how you’ve overcome the logistical challenges and how it’s working out in your system. Let us know in the comment section below!