the safest way is to put your media into an established filter for 48hrs, try your local lfs n beg em to stick yours in with theirs or ask if they'll sell you some of theirs.
a quarter of my canister's media is new spare sponges for my internal fluval filters.
the more water changes you make the longer its gonna take, but i dont think the axies are gonna be strong enuf to take it without WC's.
another option is seachem's purigen but i dont know how you'll do it if you've only got an air powered filter, id also check if purigen is ok for axies 1st, do axies like tannins in their water? cos purigen removes it as well as ammonia, nitrite & nitrates.
personally i dont use it but i would if i had an emergency n i dont think yours is yet or might never be that bad, i dont mean to be a doomsayer but if you know about things you can always fall back on them, just in case.
oh n these bacteria in a bottle dont work they dont cycle the media it just treats your water as you put it in every day.
sorry about the long post got carried away.
