QT tank ammonia nitrite spike. Any suggestions?

[Cowfish]

Ok i keep an aquaclear 20 with sponge n ceramic rings cycled on a bucket with a small mantis shrimp. I add brine shrimp every day to to keep cycled n to feed the mantis. My lfs got in a huge porcupine puffer not ur normal porcupine his spikes always stand up also he's the size of a softball. So I set up an 11gal bowfront with 2-1/2 inch crushed coral 8-10lbs live rock the cycled aquaclear 20 plus an aquaclear 50 with carbon. The ammonia today is .5 nitrite .25. The puffer seems fine eating good no rapid breathing or any signs of stress but I'm still concerned. I have a canister filter on my dt should I pull a sponge from that n put in the aquaclear 50? Would that help quick or do I put the puffer in my dt with coral? He came sooner than expected before I got a 30gal up for him. 23yrs into the hobby n I pull a move like this. I got too excited n wanted him home. Kicking myself in the ass now. Any suggestions please n thanks.

 

[dale]

small water changes every day till your system catches up ... and my dogface puffer will eat most corals right away

 

[Cowfish]

Thank u for the response. I did a 25% water change n also put a sponge from my canister filter from my dt into the aquaclear 50 I had to cut it up to pack it in so hope that with daily wc's will do it. I didn't anticipate on getting him or the size but in 23yrs never seen one like him in Windsor, London or Michigan.