Quarantine Tank Filtration

[daizeUK]

I got a second-hand AquaOne 320 as an occasional-use quarantine/hospital tank.  I thought it would come with a filter but it's only got a powerhead which is supposed to connect to an undergravel filter, but there's no undergravel filter in this tank.
 
I'm a bit confused.  Is the powerhead any use at all without the undergravel filter?   What's the point in giving me a powerhead without anything to attach it to?
 
I'm not sure how to proceed.  I could try to get a replacement undergravel filter.  I could ditch the powerhead and get a small internal filter.  Either way I'm not sure how to keep it cycled since the tank will only get used occasionally.  I know I'm supposed to keep some biomedia in the main tank to keep it cycled but that's probably easier said than done if the biochamber is an integrated unit.  Anyway is it really a good idea to share material between my main tank and the tank where sick fish die?
 
Would it make more sense to forget biological filtration and rely on water changes instead?

 

[fluttermoth]

The idea of keeping mature media in your main thank is that you use it when you need the quarantine/hospital tank, then you clean it completely in hot tap water (especially if you've had fish that are sick or die in the tank), let it dry and rebuild the bacteria back up in your main tank/filter afterwards.
 
I would definitely run some sort of biological filtration; relying on water changes isn't the best way to go about it, tbh.

 

[daizeUK]

I see.  Then undergravel filtration is useless to me, I need something with removeable media.
 
What sort of filter would be best for a 28L / 7g quarantine tank?   
 
I know that the Interpet internal filter I've got in my main tank wouldn't be any good because it has a sealed biochamber and I can't remove the ceramic rings.  I'm not sure what other types of filters are out there.

 

[TwoTankAmin]

Either way I'm not sure how to keep it cycled since the tank will only get used occasionally.

 
Hint: How does one get a tank cycled in the first place?

 

[daizeUK]

The idea is to dismantle the tank for storage when not in use, so adding ammonia is not my preferred option!  I need my kitchen worksurface back and also the heater running costs can't be justified.

 

[daizeUK]

I've narrowed it down to a few mini filters
 
1) APS 200IF - £7.99 All Pond Solutions - (The cheap option)
2) Fluval mini - £11.95 Seapets
3) Interpet PF mini - £12.95 Seapets
 
Anyone recommend or dislike any of these particular models?  I've seen the inside of the APS mini and it just seems to be just a flimsy box containing one big carbon sponge.  What's inside the Fluval/Interpet mini filters?