Most users of hospital /
QT tanks keep the set up very simple. No gravel, no decorations, easy to clean filter. Then after a quarantine or medical treatment, the tank is emptied and cleaned. To re-use or start up, take some biomedia from the established tanks filter to "instant cycle" the
QT (if you use enough, it really is an instant biofilter). Or keep a sponge on the main tanks intake, and transfer the sponge over to the
QT when adding fish. AFter use, clean the sponge or dispose of it, and replace back in the main tank. If using biomedia, throw it out after you are done with the
QT.