I have to say, I believe your thinking is a bit dated.
Nobody uses under gravel filters anymore,
.
"WHAT"!!!!! Blasphemy....... I am "somebody". An Old Coot maybe but still somebody. But I am glad no one uses UG filters any more. I like having the oldest tank on here and do you know what I like even better? No, besides Supermodels. I like having the oldest tank "and" having the oldest tank where I never have to quarantine, "and" have the fish live forever, or at least 24 years. I like the fact that my UG filtered tank has fish in it that are immune from everything except maybe spawning to much. I also like the fact that being I don't have to quarantine, I don't lose fish in a few days. I also think ammonia, while great for cleaning windows will not build up in any tank that is even a few months old no matter how slow your fish are or what pockets they live in. I do like the OPs position on UG filters though and believe DSBs are just silly. As for experience I have fish since 1952. That was last century just after Lincoln was President. I also have salt water fish from 10 minutes after they were imported to the US. Maybe 15, I forget.
One more thing. Regular UG filters won't work in salt water, as I am the God of under gravel filters in salt water. They must be run very slow and in reverse as mine has been running, non stop since 1971, I think it was on a Tuesday, about 1:00 or 1;30 in the afternoon.


as I make tweaks to my system.
And honestly, there's no reason why you can't still do this in a fish only system or with hardy soft corals. The problem is detritus will invariably start to collect under the filter plate, causing nitrates to rise. And many corals, especially SPS, just can't handle high nitrates levels.

