taking the type of fish out of the equation, I'd say a normal FW
is much less maintenance than a SW
...mainly because SW
, especially reef, requires closely watching alkalinity, pH, calcium and salinity...plus you have to pre-mix your seawater.
Now, if you're comparing a high light, CO2
injected planted tank to a reef setup, then maintenance is about the same...both tanks have a lot of test kits, and supplements/ferilizers to keep up on.
Still, neither is that daunting of a task.