Abandoned 10G, Help Please!

[Scoobcake]

ok so my very first tank was a 10G. I have since upgraded to a 30G as I figured that would be easier to learn on VS my 10G. Well when I moved to the 30G my 10 was not yet cycled and I just kind of abandoned it. havent checked water parameters regularly, havent done any PWCs, nothing. the tank has been running around 2 months and is somewhere around 1/8 low via evaporation. I checked water parameters today and they read:

Ammonia=0-.25ppm, Nitrites=off the charts high, Nitrates=off the charts high.

I would like to either have this set up as a quarantine tank or maybe stock it I havent decided yet. Either way I'd like to stablize it. Should I change the water out entirely and if so should I dose ammonia to feed the BB? with nitrites and nitrates so high there has to be some BB established right?

Also could I swish my filter media from the 10 around in my 30 to maybe help it finish cycling faster? Thoughts?

Thanks guys and gals!

 

[jlk]

Stick the filter from your 10gal on your 30gal until you decide what you want to do with the 10gal. Or, you can continue a fishless cycle on 10gal. If you want to continue to cycle the 10, do a big pwc to reduce nitrites & re-establish the buffers, then dose it to 4ppm daily & monitor whats going on as you would for any fishless cycle. When the amm/nitrites zero out steadily, do a big pwc to reduce the nitrates to less 20ppm & its ready to stock! Your choice!