:scratchch
I wonder why you say so even after you have seen the FW 20G tall that has an undergravel system in it in club7. I have not changed water for one year and only clean the tank's glass five six times. The only time, that there was a major water change is about 2 months ago when I move it to the cafe due to weight issue. The eco environemnt is almost perfect for a year without any problem-the water is still crystal clear. In one whole year, only 5 clams die due to insufficient feeding(this is an uncontrolled observation though). I added some new stuff to the tank at the beginning of 2007 and hopefully I have the time to document the whole thing for everyone to share.
The other tank, that I have an UG, has already been given to Waterplant, so you would not have seen it.
If you were thinking of the tank where your Africians are in, that tank does not even have a filter-only crush corals as substrates and an air stone in the middle of the water. That means not an UG either. That tank was just a holding tank for the big fish to be relocated into my pond during spring or if Idecide to build a big FW tank in the cafe in PA.
The key to has a successful UG system is the balance of materials and inhabitants. You need a lot of substrate and limit the choice of your live stock. If you set it up properly it actually require less maintenance than canister filter. However, you must DIY your own system because most commercial UG are incomplete.
No comments on UG in reef environment because the ones I have in SW are not even one year yet.