After 3y of keeping a reef tank i've decided to change to a goldfish tank after new year. I've already sold my corals and fish, cleaned the tank with vinegar to get rid of the lime and salt spots, cleaned the equipment and all is ready for the next big step. Reef tanks come with a sump. There's some of the equipment i still can use (return pump, led light, maybe heater). Now was my question what i should be using in the sump for filtration. The tank 55g (red sea reefer 250) with overflow comes with 2 filter bags in the sump that can do the mechanical pre-filtering.
I was thinking of adding a powerfilter. Where's the best place for this, in the sump or the main tank ? Then add a 3L bag with bioballs. Then 2L bag of Siporax ceramic rings. Would i need an uv-lamp too ? Is this too much for let's say 3 fish (Oranda/Ryukin/Veiltail - i'm not gonna add more fish) ? An airpump is also on my list. I do have several formats of wavemakers, but i think they don't use that in goldfish tanks.
I would do a fine layer of black sand 1-3mm on the bottom, together with some pebble stones/wood piece to attach some easier water plants (Anubia, Vallisneria, Elodea Densa, Rotala, Echinodorus amazonicus) that are good for goldfish and that don't need any extra co2 input. So a black backwall, black bottom, some green plants with pebble stones and colorful fish that stand out against the black.
Any help/advise is very very welcome.