Mary Burns wrote,
I agree with not using an UG for angels. I have recently removed it on one
of my angel tanks, where they were not doing as well as others without UG
filters, despite same food and water changes. Since, they have really grown
and no one is sick at all. I don't know why, but as they are thriving now.......

UGF pull the uneaten foods and solid fish waste down into the gravel
where it decomposes and slowly dissolves, becoming DOCs (dissolved
organic compounds - organic pollution). With UGFs, unlike any other
filters that are cleaned once in a while, these pollutants slowly
build-up and poison the tank. Meanwhile, this build-up of DOCs create
conditions that encourage disease, parasites and opportunistic bacteria
that remain within the tank, where as, with other filters these
conditions are in the filter and removed every once in a while. Now we
know those UGFs are out dated - they infact become the source of
organic pollution...
RF (reverse flow) UGFs are a different story. The waters flow pushes up
through the gravel, keeping the uneaten foods and solid fish waste atop
the gravel for a siphon or power filter to pick-up. In an unplanted
tank, a set-up like that would be hard to beat.

My
spawning pairs have a barebottom part where they always spawn in the same
place and just a small amount of gravel with live plants on the other side......

My breeding tanks were all bare bottom with sponge or box filters - the
few plants I had were potted. However, my grow-out tanks all had UGF -
so did the first 3 stores we opened. The gravel size over the filter
plates were be at least 3/8" - 1/2" to 3/4" worked even better, and
once every couple of weeks, the under-side of the filter plates were
siphoned out by running the siphon hose down the lift tubes and under
the plates. A lot of work, but at least the water quality was kept good
that way, and we didn't have to break down the tanks once or twice a
year like Mister Gardener did.

They look after the babies/wigglers on the bare side and always move them to
the planted area as they become free swimmers.....

I always removed the eggs - that way the breeders would spawn once a
week or week and a half. My breeders were picked from the group at 2 or
3 weeks old - the largest of the spawn and fed 5 and 6 times a day.
They were raised in deep tanks with good water flow, 20% daily water
changes and at 5 gals. per fish. By the time they were pairing off,
they were almost twice the size of their brothers and sisters, as was
their spawn size..................... Frank