I've read that it can be beneficial for your ceph to use real sea water, from the ocean, if you have access to it. I live very near the pacific ocean. Has anyone else had success collecting sea water and using that in their ceph tank?
Actually, that's not such a great idea. Most of the sea water around the shore is somewhat contaminated, so it is often filtered in some way before use. Another method is to collect it many miles out from the shore.
The best way is to make friends with a fisherman who can collect water from at least 1/2 mile from the shore. When you see the chemical readout from shorewater, I have a hard time believing people swim in that gunk.
Several southern California LFSes sell seawater that's been collected out by Catalina Island. You still have to pay for it, but someone else did all the hard work. I don't know if anyone here has used it for cephs, though, but I'd expect it to be a good choice.
I live in Santa Cruz. Nearby is the UC's Long Marine Lab, I was thinking about contacting them to see if they could provide me with filtered sea water, or at least point me towards someone that could. I don't have an RO unit, but here's what I'm thinking:
Currently I have 2 freshwater tanks setup adjacent to each other (a 100g and a 40g), sharing a filtration system, inhabited by two turtles. The turtles are going to move into a stock tank (like a big plastic tub), to free up the glass tanks for a ceph. The octo is going to live in the 100g, and I'm going to treat the 40g as an emergency reservoir, so that if I need to do a water change I'll be able to do a 40% easily. I was also going to pick up a 30g trash can or similar and use that as well. Am I being silly? Is it better to just go for the RO/DI unit?
I know that in San Diego a majority of the hobbyists enjoy free water off of the Scripps Pier. It's pumped up from farther away from shore and in deeper water. It also gets filtered through 3 deep sand beds that filter out any plankton and other crap that may have gone through giving you clean, pretty much nutrient free water.