
to ReefLounge!
while the eclipse 6 does make a great "all inclusive" tank, most people make a few custom alterations to make the setup a bit better...lights being the most commonly upgrade. most people retrofit a higher wattage power compact ballast for better reef lighting. also, personally i would add a small heater, but most with that use an eclipse 6 don't use a heater in their setups...it all depends on how warm or cold the tank gets after setup.
in terms of expense, the eclipse is relatively affordable in costs, as well as maintenance and up-keep. it should prove to be an easy tank to take care of.
now, here's the downside...i assume your parents have no reef-keeping experience. in a tank with smaller water proportions, water conditions can quickly foul up, and throw the entire tank in to a bad situation, and could even wipe out the whole tank. think of it this way...if you had a glass of water, and a bathtub full of water, and dropped a single drop of red food coloring in the water, which water would quickly become pink in color? now think of that in terms of poor water conditions...
while "nano" (the term commonly used for small, or micro tanks) setups reap benefits, they can appear to be more difficult to take care of. i have no problem thinking that your parents can be educated, and learn all about the upkeep of a reef, even in a nano setup. i know it intends to be a surprise for them, but talk it over with them...make sure they're ready for the "work" involved in having a reef tank. let it be said, that i personally believe reef tanks (setup properly) are the easiest to take care of. while that's only my opinion, i'm sure many will agree.
take a look at my tank...it's only a 25 gallon tank, but pretty easy to maintain, and a little like the eclipse setup. BEST OF LUCK!!!