Ive just read through this thread and thought I should respond, Im not sure how many people in this forum know this, but I used to work at a fish store specializing in just salt water aquariums, I then quit that job to go be the reef tank expert at another store and ended up working there until I finished college.
I have set up and maintained many small reef aquariums ranging from a goldfish bowl full of mushroom anemones, zoanthids, and shrimp. *This thrived until my coworkers got sick and tired of explaining to the customers why they couldnt due that at home! My favorite size reef aquarium is probably 10 gallons, the biggest problem I ever ran into was competition between the different corals, I was constantly pruning.
My advise for setting up a small salt water aquarium is:
* *-Keep it simple
* *-Its easy to light up a small aquarium so use alot of light!
* * * * * * I would use at least 8 watts per gallon
* *-Start with purified water (ro) and a high quality salt mix
* *-Use lots of high quality live rock (well cured)
* *-lots of current (you want to see most corals really moving
* *-forget the biological/mechanic filter, they are usuless here
* * * * * the live rock will provide all the necessary filtration
* *-keep nitrates at 0 ppm (maybe up to 5ppm would be
* * * * * acceptable
* *-and remove as much organics as possible, either through
* * * * *use of a skimmer, or in the case of a really small tank,
* * * * *large daily water chgs, most of the corals we keep in
* * * * *aquariums are very resistant to fluctuations in salinity
* * * * *and temperature caused by the tides, very few corals
* * * * *we keep in aquariums are actually collected from the
* * * * *outer reef......IMHO it wont hurt your corals to due a
* * * * *75% or larger water chg (certain exceptions do apply)
* * * * *and in my opinion they seem to due better when given
* * * * *large water chgs on a regular basis *
* * -the last super important thing is regular additions of
* * * * *trace elements and calcium etc.
Now if all that is adhered to a small salt water aquarium should be really simple to maintain. But..you might be asking about fish? Generally speaking on the really small aquariums I would include none....on larger aquariums maybe one or 2, I would follow my keep the nitrates at 0 ppm rule on this!
Personally I would never use an undergravel filter or biowheel filter on a saltwater aquarium, they may work short term but not long.
Hope this helps!
This is part of a 5 gallon reef aquarium