How to stop or neutralize the effects of bleach tablet in a RV holding tank?

ok we have some bleach / chlorine tablets like for a pool and i guess some one thought it would be refreshing for the holding take and lo and behold smoke comes pluming out of the toilet " yes I know it is a toxic smoke and bleach should never be put in a toilet in concentrated amount but it was " and now i have no idea what to do the pump doesn't work so i need to neutralize it or something please help i have the area well ventilated and shut off but of cores when we use it we let some of the now little traces of gas out